Qutab Minar, Delhi
Built by Qutab-ud-din Aibak, the first Muslim ruler of Delhi the Qutab Minar is a 73 m-high tower built in 1193. The tower has five storeys, each marked by a projecting balcony and tapers from a 15 m diameter at the base to just 2.5 m at the top. The first three storeys are made of red sandstone; the fourth and fifth storeys are of marble and sandstone. Qutab-ud-din Aibak, the first Muslim ruler of Delhi could only finish the basement. His successor, Iltutmush, added three more storeys, and in 1368, Firoz Shah Tughlak constructed the fifth and the last storey. At the foot of the tower is the Quwwat-ul-Islam Mosque, the first mosque to be built in India.