15 km south of New Delhi, the Qutab Minar rises high into the firmament over looking an entire area  - named Mehrauli – which is dotted with ruins of Islamic monuments. The minar or tower itself is 73 metres high, its diameter 15 metre at the base and just 2 and a ½ metres at the top. It has five distinct storeys, the first three are of red sandstone, and the fourth and fifth of marble and sandstone. Each storey has a projecting balcony. The ornamental work on the tower only reinforces the impressive stature of the tower. It was started in 1193, after the last Hindu kingdom in Delhi fell to the Afghan invader Qutab-ud-din. The Qutab Minar complex contains Quwwat-ul-Islam mosque, the first mosque to be built in India. It was surrounded in early 13th century by a cloistered court by Iltutmish, and in early 14th century by a red sandstone gateway( the Alai Darwaza) by Ala-ud-din. To the north of the Qutab Minar and the mosque, stands an unfinished minar 27 metres high, This is the Ala-i Minar, begun by Ala-ud-din but abandoned after his death. Beside the Ala-i Darwaza lies the tomb of Imam Zamin and Iltutmish's tomb is by the north-west of the mosque. In the courtyard of the mosque stands a 7-metre-high iron pillar, which is one of the wonders of India. It was brought from elsewhere and erected there by the Hindu king Chandra Varman in the 5th century. Its origins may have been in the Gupta period. Indications that it had once been crowned by the figure of the mythical bird Garuda who carries the Hindu god Vishnu on his back suggest that the pillar had originally belonged to a temple dedicated to a Vishnu temple. The iron in the pillar is of such inexplicable purity that it has not rusted in all these centuries. It testifies to the fact that ancient India had acquired great metallurgical skills. Most everyone who visits the Qutab Minar tries to encircle the iron pillar with one's back to the pillar. It is supposed to be wish-fulfilling.