Iron Pillar

New Delhi, India

The iron pillar of Delhi is a 7 m (23 ft) kirti stambha (column of fame or victory column), originally erected and dedicated as dhvaja (banner) to Hindu deity lord Vishnu in 3rd to 4th century CE by king Chandra, currently standing in the Qutb complex at Mehrauli in Delhi, India. It is notable for the rust-resistant composition of the metals used in its construction. The pillar has attracted the attention of archaeologists and materials scientists because of its high resistance to corrosion and has been called a "testimony to the high level of skill achieved by the ancient Indian iron smiths in the extraction and processing of iron." The corrosion resistance results from an even layer of crystalline iron hydrogen phosphate hydrate forming on the high-phosphorus-content iron, which serves to protect it from the effects of the Delhi climate. The pillar weighs over 6,000 kg (13,000 lb) and is thought to have originally been erected in what is now Udayagiri by one of the Gupta monarchs in approximately 402 CE, though the precise date and location are a matter of dispute. The Qutb complex , also spelled Qutab complex or Qutub complex , is an array of monuments and buildings at Mehrauli in Delhi, India. The best-known structure in the complex is the Qutub Minar, built to honor the Sufi saint Qutbuddin Bakhtiar Kaki. Its foundation was laid by Qutb-ud-din Aibak, who later became the first Sultan of Delhi of the Mamluk dynasty. The Minar was added upon by his successor Iltutmish (a.k.a. Altamash), and much later by Firoz Shah Tughlaq, a Sultan of Delhi from the Tughlaq dynasty in 1368 AD. The Qubbat-ul-Islam Mosque (Dome of Islam), later corrupted into Quwwat-ul Islam, stands next to the Qutb Minar. It was built on the ruins of Lal Kot Fort (built by Anangpal, the Tomar ruler, in 739 CE) and Qila-Rai-Pithora (the Chauhan emperor Prithviraj Chauhan's city), whom Ghori's Afghan armies had earlier defeated and killed in the Second Battle of Tarain. The complex was added to by many subsequent rulers, including the Tughlaqs, Alauddin Khalji and the British. Apart from the Qutb Minar and the Quwwat ul-Islam Mosque, other structures in the complex include the Alai Gate, the Alai Minar, the Iron pillar, the ruins of several earlier Jain temples, and the tombs of Iltutmish, Alauddin Khalji and Imam Zamin. Today, the adjoining area spread over with a host of old monuments, including Balban's tomb, has been developed by the Archaeological Survey of India (ASI) as the Mehrauli Archaeological Park, and INTACH has restored some 40 monuments in the Park. It is also the venue of the annual 'Qutub Festival', held in November–December, where artists, musicians and dancers perform over three days. The Qutb Minar complex, which drew 3.9 million visitors in 2006, was India's most visited monument that year, ahead of the Taj Mahal (with 2.5 million visitors) #InStone