This 1,600-year-old iron pillar is still standing with remarkably little corrosion Forged during the Gupta period in India, the Delhi Iron Pillar has survived

This 1,600-year-old iron pillar is still standing with remarkably little corrosion Forged during the Gupta period in India, the Delhi Iron Pillar has survived for centuries thanks in part to its phosphorus-rich iron and naturally formed protective surface layer