Iron Pillar

In the centre of the mosque. True to its name, this is a 7 m iron pillar erected in 400 AD by Chandragupta II Vikramaditya, also known as "he, by the breezes of whose prowess the southern ocean is even still perfumed" according to the inscription carved on the base. Alas, Chandragupta II's perfume has long since faded, but to the amazement of metallurgists everywhere, his pillar is still going strong, after 1,600 years. The corrosion resistance results from a layer of crystalline iron hydrogen phosphate forming on the high phosphorus content iron, which protects it from the effects of the local Delhi climate. The pillar is 7.21 m high, 1.12 m of which is below ground. The base rests on a grid of iron bars soldered with lead into the upper layer of the dressed stone pavement. It is estimated to weigh more than six tonnes.