Mystery of Delhi's Rustless Iron Pillar

[00:00:00]What ancient secret keeps a 1,600 [music] year-old iron pillar standing strong and rust-free in Delhi?

[00:00:06]Erected around the 4th century CE, this massive column weighs over 6 tons and has baffled scientists for decades.

[00:00:14]Unlike most iron structures, it refuses to corrode despite centuries of rain and heat. The secret lies in its unique composition, a high phosphorus content and lack of sulfur or magnesium, which forms a protective film over the metal. This astonishing feat of metallurgy showcases the advanced knowledge and craftsmanship of early Indian blacksmiths.