How America Built a 55-Foot Stone Dam to Carry Water 41 Miles to New York by Hand

Added: 2026-06-02

[00:00:00]On the morning of January 8th, 1841, a laborer named Michael Burke was asleep in a workman's shanty on the bank of the Croton River, about 40 miles north of New York City.

[00:00:12]Above him stood an unfinished wall of stone and earth that thousands of men had been building for nearly 4 years.

[00:00:19]That wall was meant to tame a river and carry its water all the way down to Manhattan.

[00:00:24]Before the sun was fully up, the river took the wall, and it took Michael Burke with it.

[00:00:29]His body was found 3 miles downstream.

[00:00:32]>> [music] >> The man who had to answer for that dam was an engineer named John B.

[00:00:37]Jervis, [music] and he had begun his own working life as a teenage axman clearing brush for the Erie Canal.

[00:00:44]I went looking for the full story of how a city of hundreds of thousands of people decided to drink from a wall of hand-cut stone, 55 ft high, >> [music] >> 41 miles away, moved by nothing but gravity.

[00:00:57]What I found is one of the most quietly [music] astonishing things Americans ever built. And almost no one who turns on a tap in New York today knows it happened.

[00:01:06]So, let me show you what it actually took, and why the city had no choice but to try.

[00:01:12]To understand why anyone would attempt something this large by hand, you have to understand [music] how desperate New York had become for clean water.

[00:01:19]For almost 200 years, the island of Manhattan had drunk mainly [music] from one place, a spring-fed pond near the center of the lower city that people called the Collect or the Fresh Water Pond.

[00:01:30]In the early days, it was clean and deep, deep enough that some claimed it had no bottom.

[00:01:35]There was a famous well beside it that fed [music] the Tea Water Pump, and carts carried that water through the streets for people to buy by the bucket.

[00:01:44]But Manhattan sits on hard rock and salt water [music] with no great river of its own, and a single pond cannot serve a growing city forever.

[00:01:51]As the population climbed, the tanneries and the breweries and the slaughterhouses crowded in around the collect and they poured their waste straight into it.

[00:02:00]By the early 1800s, the pond that had watered New York for two [music] centuries was a stinking sink filling with dead animals and the runoff of a hundred trades.

[00:02:09]The city eventually drained it and filled it in and the ground where it had been became the most notorious slum in America, the Five Points.

[00:02:18]The city did try to fix the problem before it reached for the Croton and the first attempt is one of the strangest chapters in the whole story.

[00:02:26]In 1799, the state handed a private company the exclusive right to supply New York with water.

[00:02:32]It was called the Manhattan Company and it was led by the politician Aaron Burr.

[00:02:39]But the men who ran it turned out to be far more interested in banking than in water.

[00:02:43]They used a clause in their own charter to open a bank instead and they gave the city's water the smallest effort they could get away with.

[00:02:51]They sank a well near the old pond, built a modest reservoir on Chamber Street holding a little more than 500,000 gallons and laid about 6 miles of pipe to distribute it.

[00:03:01]Those pipes were not iron.

[00:03:03]They were the trunks of yellow pine trees hollowed out with an auger, the bark left on, tapered at one end to fit into the next and bound together with wrought iron bands.

[00:03:13]That wooden network reached only about 400 families and the water it carried was no better than what the city already had.

[00:03:20]For another full generation, New York drank badly and waited.

[00:03:25]Then came the two disasters that ended the waiting.

[00:03:28]In 1832, a cholera epidemic swept through the city and killed more than 3,000 people in a single summer.

[00:03:34]Anyone who could afford to leave fled the island.

[00:03:38]The dying was worst exactly where the water was worst, in the crowded low blocks near the filled-in pond [music] and the lesson was impossible to miss.

[00:03:46]Three years later, in December of 1835, came the second blow.

[00:03:51]A fire broke out among the warehouses of lower Manhattan on one of the coldest nights of the year.

[00:03:56]The cisterns were frozen solid.

[00:03:59]The wells were too shallow and too far apart.

[00:04:02]The firefighters watched their hoses ice over and their water give out, and the fire burned through the night until it had leveled hundreds of buildings across the commercial heart of the city.

[00:04:12]New York learned the same brutal lesson [music] twice in 3 years.

[00:04:16]A great city without water is a city waiting for a catastrophe.

[00:04:19]So, the city finally committed to the only answer big enough to matter.

[00:04:24]In 1835, New Yorkers voted to dam the Croton River far to the north in Westchester County and to build a closed channel of brick and stone to carry that water more than 40 miles [music] down to the city.

[00:04:38]To a great many careful men of the time, the plan sounded like madness.

[00:04:43]There would be no pumps anywhere along the line.

[00:04:46]There would be no steam engines lifting the water.

[00:04:48]The entire system would run on gravity alone on the simple fact that the Croton sits a little higher than Manhattan.

[00:04:55]And water given a steady downward path will always travel toward the sea.

[00:05:00]The first man given the job of finding that path was David Bates Douglas, a former army engineer and a professor at West Point.

[00:05:08]Douglas walked the country [music] and surveyed the route and laid out the basic line the water would follow.

[00:05:14]But, the work under him moved slowly.

[00:05:16]The costs frightened the commissioners.

[00:05:19]And in October of 1836, they removed [music] him.

[00:05:22]In his place, they appointed John B.

[00:05:25]Jervis.

[00:05:26]And here is the detail I keep coming back to because it ties this whole story together.

[00:05:32]Jervis was not [music] a university man.

[00:05:35]He had almost no formal schooling as an engineer at all.

[00:05:38]He had started out decades earlier as a common axeman.

[00:05:41]A young man swinging a blade to clear the route of the Erie Canal across upstate New York.

[00:05:46]He learned his trade by doing it mile by mile on the greatest hand dug waterway the country had ever built and he rose from there through the canals and the early railroads on sheer competence.

[00:05:58]The man New York trusted to finish its water supply had learned everything he knew on the Erie Canal by hand.

[00:06:05]The teacher and the student were the same river country 20 years apart.

[00:06:10]If the idea of moving an entire river by hand is the kind of history you came here for, I want to tell you that the story that started all of this, the Erie Canal that taught John B.

[00:06:21]Jervis his trade is now a book.

[00:06:24]The full illustrated account of how it was dug across New York with shovels and wheelbarrows.

[00:06:29]You can scan the code on your screen and start reading it tonight. Jervis took the survey that Douglas had left him and turned it into a set of demands so exact that they still impress engineers today.

[00:06:40]The aqueduct would run 41 miles and along that entire distance it would drop just 13 inches per mile.

[00:06:47]Stop and feel how fine that is.

[00:06:49]Over a length of more than 40 miles, the channel falls about as much as the height of a tall man and not 1 inch more than it has to.

[00:06:59]Too steep >> [music] >> and the water would race and tear the masonry apart.

[00:07:02]Too flat and it would sit still and turn stagnant.

[00:07:06]Jervis chose a slope gentle enough to keep the water moving at a slow walk and firm enough to keep it fresh and then he held his crews to it across a distance [music] you would drive for the better part of an hour today.

[00:07:16]The channel itself was not a pipe in the way we picture pipes.

[00:07:21]It was a tunnel you could walk through shaped like a horseshoe built of brick and [music] cut stone about 8 and 1/2 feet high and 7 and 1/2 feet wide.

[00:07:31]A grown man could stand up inside it [music] with room to spare.

[00:07:35]The crews lined the inside with brick laid so smoothly that the water would meet almost no resistance set in a hydraulic cement that would harden even under water, and they wrapped the whole channel in masonry [music] and packed earth to hold it against the frost.

[00:07:50]Every mile or so, they raised a stone ventilator tower, so the moving water could breathe and [music] the pressure could never build to a point that split the walls.

[00:07:58]41 miles of hand-laid brick tunnel, falling 13 in in every mile, >> [music] >> running south through the valleys and ridges of Westchester, past Sing Sing and Tarrytown and Yonkers, toward the river that guarded Manhattan.

[00:08:11]Holding that grade across 41 miles of real country was the harder half of the job.

[00:08:17]The land between the Croton and the city is not flat.

[00:08:20]It rises into rocky ridges and drops into stream valleys, and the channel could not simply follow the ground because the ground does not fall at a steady 13 in a mile.

[00:08:31]So, the engineers forced the line to keep its slope, no matter what the terrain did.

[00:08:35]Where a hill stood in the way, they cut straight through it.

[00:08:39]Where the rock would not open to a cut, they bored a tunnel.

[00:08:43]The finished aqueduct ran through 16 separate tunnels, the longest of them more than 1,200 ft of hand-driven passage through solid rock.

[00:08:51]Where a valley or a stream crossed the path, they carried the channel over it on stone, and the line passed [music] over flowing water in more than 100 masonry culverts, some only a foot or two across, others wide enough to span a creek.

[00:09:04]Every one of those crossings had to meet the same exact grade, so the water never knew it had left the level.

[00:09:10]And remember that they laid this whole slope out with the plain instruments of the 1830s, levels and chains and sighting transits, measuring the fall of the land a few hundred feet at a time, and summing those tiny drops across 41 miles until they had one continuous, almost invisible descent.

[00:09:29]The channel they held to that line could carry as much as 90 million gallons of water a day, an ocean moving in the dark at a slow walk.

[00:09:38]The most striking of those crossings still stands in the village of Ossining, the old [music] Sing Sing.

[00:09:44]There the aqueduct had to cross a deep ravine cut by the Sing Sing Kill, >> [music] >> and the masons answered it with a great stone arch, 88 ft long and 76 ft high, built of granite and nice and lined with brick.

[00:09:58]Then they carried a village road across on a second arch above the first.

[00:10:02]So, the whole structure became known as the double arch with water passing through one arch and people passing over another.

[00:10:09]It is a small masterpiece and it has stood for more than 180 years.

[00:10:14]To keep the long channel clean, the engineers also set waste weirs at intervals along the line, stone chambers with gates that let the keepers drain a stretch of the aqueduct and flush it out so the water that reached the city stayed clear.

[00:10:28]None of it was decoration.

[00:10:30]Every cut, [music] every tunnel, every arch, and every weir existed for one reason, to keep a river falling 13 in >> [music] >> a mile all the way to Manhattan.

[00:10:40]And at the head of all of it stood the dam.

[00:10:42]The Croton Dam was a wall of cut stone about 55 ft high, some 70 ft thick at its base, narrowing to 7 ft at the top, and roughly 250 ft across the river.

[00:10:54]Behind it, the river backed up into a reservoir 5 mi long, covering 400 acres, holding 500 million gallons of water waiting to begin its journey.

[00:11:04]Building a stone wall that size across a living river is its own quiet [music] act of nerve.

[00:11:10]The crews had to push the river aside while they worked, hold it back behind temporary barriers, dig down through mud and gravel until they reached solid bedrock, [music] and only then begin to raise the masonry from a foundation that the current could never undermine.

[00:11:24]The dam did not just block the Croton.

[00:11:26]It lifted it, gathered it, and aimed it down the long stone throat of the aqueduct toward the city.

[00:11:33]Now, hold the engineering in your mind for a moment and look at the hands that did the work because this is where the real weight of it lives.

[00:11:40]The dam and the aqueduct were built by thousands of laborers.

[00:11:44]And most of them were Irish immigrants.

[00:11:47]Men who had crossed the ocean into a country that needed their backs and offered them very little in return.

[00:11:53]They worked for less than a dollar a day.

[00:11:55]They lived in rough shanties strung out along the line of the works in the river valleys and the rock cuttings through the heat of summer and the deep cold of a Hudson Valley winter.

[00:12:07]The tools they used were the tools of the age before machines.

[00:12:11]Picks, shovels, hammers and hand drills for the rock, black powder to break the stone ledges that would not yield to iron.

[00:12:21]Mule carts and wheelbarrows to haul the cut stone and carry away the spoil.

[00:12:26]There was no excavator anywhere on that line, no crane, no engine doing the lifting.

[00:12:31]There were only men and animals and gravity and time.

[00:12:35]I want to be careful here because it would be easy to make this sound romantic and the men who did it would not have called it romantic.

[00:12:42]Breaking rock with black powder killed and maimed workers in numbers the records only partly captured.

[00:12:48]Cave-ins, falling stone, drowning in the works, the ordinary violence of moving heavy things by muscle, all of it took a steady toll across the four years of the job.

[00:12:59]For most of those men, the ledger gives no name, only a number.

[00:13:03]They were hired, counted, and replaced.

[00:13:07]But the thing they built did not fail and it did not cut corners because the man at the top would not let it.

[00:13:12]Jervis wrote specifications for every segment of the line and walked it himself and he is remembered for one rule in particular that tells you how serious he was.

[00:13:22]He discouraged liquor anywhere near the cuttings on a job where cheap drink was the usual comfort of hard labor, because he would not gamble the precision of the masonry on a shaking hand.

[00:13:32]He wanted the water [music] to run clean for 100 years, and he understood that a channel falling 13 in a mile does not forgive sloppy work.

[00:13:40]It is worth pausing on those camps because for 4 years they were among the largest temporary settlements in the state.

[00:13:45]The shanty towns that followed the line were not only bunkhouses for single [music] men.

[00:13:50]Whole families came with the work.

[00:13:52]There were women cooking and washing, children born along the cuttings, rough chapels and grog shops, and small gardens scratched into the Westchester hillsides.

[00:14:02]When one section of the line was finished, the camp packed up and moved south to the next, a town on the move, chasing the slow southward crawl of the stone channel.

[00:14:11]These were people the respectable city tended to look down on, immigrants with brogues and split hands, and yet the comfort and safety of every household in Manhattan was about to rest entirely on the quality of their labor.

[00:14:24]The clean water that a wealthy family on [music] Fifth Avenue would one day draw without a second thought had been laid brick by brick by Irish hands in a shanty camp 40 miles up the river.

[00:14:36]That is the part of the story the fountains never [music] showed.

[00:14:39]There was one place on the whole line where gravity and geography flatly refused to cooperate, and it produced the single most beautiful piece of the entire system.

[00:14:50]The aqueduct had to cross the Harlem River to reach Manhattan, and the river traffic and the law demanded a high crossing that ships could pass beneath.

[00:14:58][music] So, they built a bridge of stone.

[00:15:02]High Bridge rose 140 [music] ft above the Harlem River, carried on 15 stone arches, >> [music] >> 1,450 ft long.

[00:15:11]A Roman aqueduct reborn in American granite.

[00:15:16]It took years, and it was not finished [music] until May of 1848, several years after the water first reached [music] the city.

[00:15:24]Until then, the water crossed the Harlem through a temporary pipe laid low across the river while the great arches climbed slowly above it.

[00:15:33]But High Bridge became the soul of the project. The part you could stand beneath and crane your neck at and finally feel the scale of what had been done.

[00:15:43]High Bridge still stands today.

[00:15:46]It is the oldest standing bridge in New York City.

[00:15:49]And though the water it was built to carry has long since been routed elsewhere, the arches are exactly where the stonemasons left them.

[00:15:56]At the city end of the line, the water arrived into two great reservoirs that most New Yorkers walk past today without any idea of what once stood there.

[00:16:06]The receiving reservoir sat where Central Park is now, a vast walled basin of water more than 1,800 ft long holding up to 180 million gallons.

[00:16:17]The distributing reservoir stood farther downtown at 42nd Street, a stern Egyptian-styled fortress of stone walls where fashionable New Yorkers strolled along the top to take the air and look out over the city.

[00:16:29]That reservoir is gone now.

[00:16:31]The New York Public Library and Bryant Park stand on the exact ground it occupied.

[00:16:36]So the next time you see a photograph of those famous stone lions on Fifth Avenue, understand that they sit on the footprint of a reservoir that once held the Croton River brought there by hand.

[00:16:47]If you are new here and this is the kind [music] of history you have been looking for, the quiet engineering and the named men behind the things we take for granted, take a second to subscribe or to join the channel as a member for early access to every [music] new film.

[00:17:01]It is the simplest way to keep work like this going.

[00:17:04]Now, we come back to the river and to the worst day of the whole project because the Croton did not give up its water without a fight.

[00:17:12]Through 1840 and into the winter of 1841, the dam was still unfinished.

[00:17:18]The Masonry section was rising, but a large part of the structure across the river was still an earthen embankment. A great bank of packed soil holding back the rising reservoir while the stonework [music] caught up.

[00:17:30]That earthen bank was the weak point.

[00:17:32]And the winter of 1841 found it.

[00:17:36]It began with a thaw.

[00:17:38]On about the 5th of January, after a hard freeze, the weather turned warm and the rain came down on top of the melting snow across the whole Croton watershed.

[00:17:47]Every frozen stream and hillside let go at once.

[00:17:50]The river rose fast, faster than anyone on the works had seen it, carrying broken ice and torn timber [music] down toward the half-built dam.

[00:17:59]By the morning of the 8th of January, the water had climbed to the very top of the earthen embankment, and then it began to pour over it.

[00:18:07]Once water runs over the top of an earthen dam, the end comes quickly.

[00:18:11]The overflow cut into the soil. The cut deepened with every second.

[00:18:15]And within about an hour, the embankment gave way and released everything the reservoir was holding.

[00:18:21]What came down the Croton Valley that morning was not a flood in the ordinary sense.

[00:18:26]It was a moving wall of water and ice and wreckage, [music] and it carried off everything in the flood plain.

[00:18:31]Michael Burke was in his shanty below the dam when it failed.

[00:18:35]He never had a chance to climb clear.

[00:18:37]The flood swept the shanty off its footing and carried him down the river, and his body was found 3 miles below the dam.

[00:18:46]He was not the only loss along the valley that day, but he is the name the record kept, and so he is the name we keep.

[00:18:53]Down the length of the lower Croton, the water destroyed every bridge it reached, wrecked mills and homes, and set the river back for years.

[00:19:01]The damage was counted at $700,000, an enormous figure for 1841, and a hard verdict on the decision to trust a wall of packed earth to do a job that needed stone.

[00:19:13]For John [music] B.

[00:19:14]Jervis, the failure was both a disaster and a lesson he refused to waste.

[00:19:19]He did not simply rebuild what had washed away.

[00:19:23]He went back to the design and asked why the river had won.

[00:19:26]And he changed the dam so that it could never win the same way again.

[00:19:32]The new embankment was built far stronger and tied more deeply into the banks.

[00:19:36]But the real stroke of insight was in the spillway. The part of the dam meant to let floodwater pass without harm.

[00:19:43]Jervis gave the dam a long curved profile. A smooth sweeping face shaped so that when the river ran high the water would flow up and over the crest and slide down the curve in a controlled [music] sheet.

[00:19:55]Breaking its own force against the stone instead of tearing the structure apart.

[00:19:59]He took the dam's single greatest danger, the moment of overflow, >> [music] >> and turned it into the very thing the dam was built to survive.

[00:20:07]The rebuilt Croton Dam with its curved stone spillway held the river from the 1840s all the way until 1906 when a larger New Croton Dam was finally built 3 miles downstream to take its place.

[00:20:20]More than 60 years of floods and it never failed again.

[00:20:24]By the summer of 1842, the line was so nearly complete that the engineers could inspect [music] it from the inside.

[00:20:30]And they did it in one of the strangest images of the whole project.

[00:20:34]A small boat that the men called the Croton Maid was carried up to the aqueduct and floated through a long finished stretch of the empty [music] stone channel. Gliding by lantern light through the cool dark tunnel, drifting along the very grade that would soon carry a river.

[00:20:50]For a few quiet weeks, men rode a boat through a tunnel that held no water [music] yet. Riding the slope they had cut and laid by hand. Checking the work one last time before they let the Croton in.

[00:21:02]So the men went back to work and they finished it.

[00:21:05]And on the 22nd of June, 1842, after years of digging and blasting and laying brick by hand, the gates were opened and the Croton River began its long, slow walk to the city.

[00:21:17]The water took about 22 hours to travel the full 41 [music] miles, moving at a little under 2 miles an hour, sliding down that gentle 13-in grade through the dark stone [music] channel, across the Harlem River, and into the reservoirs of Manhattan.

[00:21:32]People rode out along the line to watch the first water [music] move through the aqueduct, and word ran down to the city ahead of the river itself.

[00:21:39]The formal celebration came on the 14th of October, 1842, and the young city threw itself into it with everything it had.

[00:21:48]New Yorkers held what was at that time the largest parade the city had ever staged, a procession that stretched some 7 miles and drew a crowd estimated at a quarter of a million people lining Broadway.

[00:22:01]The city had commissioned a song for the occasion, the Croton Ode, written by George Pope Morris, and it was sung in front of the new fountain by members of the New York Sacred Music Society.

[00:22:11]And in City Hall Park, the centerpiece, a fountain fed by the Croton sent a jet of clean, sparkling water 50 ft straight up into the air in the middle of the city on demand >> [music] >> with no one pumping it.

[00:22:25]For tens of thousands of New Yorkers, it was the first time in their lives they had ever seen such a thing.

[00:22:31]A city that had buried 3,000 of its own a decade earlier and watched its heart burn for want of water stood in the autumn light and looked at a column of clean water leaping out of a river that began 41 miles to the north.

[00:22:45]Behind the fountains and the 7-mile parade was a second, quieter network that actually finished the job.

[00:22:52]The water that reached the reservoir still had to get into the streets and the houses, and so the city laid down a web of cast iron pipe beneath the [music] pavement following the grid of the growing city.

[00:23:03]In time, that distribution system ran to something like 130 miles of iron pipe carrying Croton water under the streets of Manhattan.

[00:23:11]For the first time, an ordinary household could have clean water piped directly indoors for about $10 a year.

[00:23:20]And for those who could not pay even that, the city opened free public hydrants along the streets where anyone could fill a bucket at no cost at all.

[00:23:29]Those same hydrants finally gave the fire companies what they had begged for on the night the city burned, real water at real pressure [music] on demand at the corner.

[00:23:39]The cost of all of it was staggering for the time.

[00:23:42]The dam, the reservoir, the 41 miles of aqueduct, and the [music] Westchester land came to more than 8 and 1/2 million dollars.

[00:23:52]And once the city pipes and the interest on the loans were counted, the whole undertaking reached something on the order of 13 million dollars.

[00:24:00]There were men who had called that price insane when the work began, [music] who swore the city would bankrupt itself chasing water from a river nobody downtown had ever seen.

[00:24:09]They were wrong, and the proof was pouring out of every hydrant in lower Manhattan.

[00:24:14]What the Croton brought was not only public health and fire protection, though it brought both. And the cholera that had terrified the city loosened its grip as clean water spread.

[00:24:25]When the disease swept through American cities again in the decades that followed, New York suffered far less [music] than it once had, and the abundance of clean Croton water was a large part of the reason why.

[00:24:36]It also began to change the inside of the ordinary home.

[00:24:40]With a steady supply of running water under pressure, indoor plumbing slowly became possible, and over the following decades, the bathtub and the indoor tap, and eventually the modern bathroom, spread out from New York into American life.

[00:24:54]A wall of stone on a river in Westchester quietly rewrote what it meant to live in a city.

[00:25:00]And the influence ran well past New York itself.

[00:25:03]The Croton proved that a modern American city could solve its water for good by reaching deep into the countryside and building big in stone.

[00:25:10]And other cities studied exactly how it had been done.

[00:25:13]Within a few years, Boston had built its own great aqueduct, the Cochituate, to carry distant water across miles of country into the city, opening in 1848.

[00:25:24]Over the rest of the century, one American city after another followed the path New York had cut, gathering rivers behind masonry dams, driving tunnels through hills, [music] and walking the water home on gravity alone.

[00:25:37]Engineers who had cut their teeth on the Croton carried what they had learned to those later projects, and the basic idea, a wall on a far river and a long stone channel falling gently toward the city, became the standard answer across the country.

[00:25:51]The wall on the Croton was not only New York's solution to an old curse.

[00:25:56]It became the template the whole nation borrowed for how a great city keeps itself alive.

[00:26:01]I think about what that water actually represented, and I keep landing on the same idea.

[00:26:07]The Croton system was not only an engineering achievement, it was a decision about what a city owed its people.

[00:26:13]New York chose to spend an enormous fortune and years of the hardest hand labor to give ordinary citizens [music] clean water as a matter of course, and the payoff is almost impossible to measure.

[00:26:24]The population the Croton water could support kept climbing, and the city that drank [music] from that river grew into the metropolis we know.

[00:26:30]It is hard to name a single public work that did more to make that growth possible.

[00:26:38]Now, I want to be honest about the legacy, because the easy version of this story is not quite true.

[00:26:44]People sometimes say the old dam still waters New York, >> [music] >> and it does not.

[00:26:48]The 1842 dam was replaced in 1906.

[00:26:52]The water New Yorkers drink today comes from far larger systems built later up in the Catskill Mountains and beyond.

[00:26:59]But the principle those later systems run on, the idea that you can water a vast city by [music] reaching deep into the countryside, gathering a river behind a wall, and letting gravity carry it home through stone and tunnel, that idea was proven on the Croton by hand in 1842.

[00:27:17]Every [music] gravity-fed drop that reaches a New York faucet today is the descendant of what those men built.

[00:27:24]And the bones of the original are still out there to be walked.

[00:27:27]The old aqueduct is a state trail now, and you can hike for miles along the top of the buried stone channel through Westchester. [music] High Bridge still vaults the Harlem River on its stone arches.

[00:27:38]The reservoir basins became Central Park and the ground beneath the great library.

[00:27:43]The work did not vanish.

[00:27:45]It became the city.

[00:27:47]Which leaves me with a harder question, and I'm going to hand it to you.

[00:27:51]We tend to assume that real progress means machines, that the truly great infrastructure had to wait for the engine and [music] the crane and the bulldozer.

[00:28:00]But the men who built the Croton had none of that, and they produced a system so well conceived that it served a growing city for more than 60 years and shaped the New York that came after.

[00:28:11]They worked to a tolerance of 13 inches a mile with picks and wheelbarrows and black powder.

[00:28:17]So here is what I keep wondering.

[00:28:19]If a crew today were handed the same problem, the same river, the same 41 miles, and the same rule that it must all run on gravity alone with no engine to lift the water, do you honestly believe we could match what those hands did in 1842?

[00:28:34]I have my own answer.

[00:28:36]I would like to hear yours down in the comments, because I do not think it is nearly as obvious as we would like to pretend.

[00:28:42]If you want the deeper origin of all of this, the Erie Canal that taught John B.

[00:28:47]Jervis everything he knew. The full illustrated story is waiting behind the code on your screen.

[00:28:53]Scan it, pick it up, and thank you for staying with me all the way to the end.

[00:28:58]I will see you with the next one.