The Qutub Minar is a soaring, 73 m-high tower of victory, built in 1193 by Qutab-ud-din Aibak immediately after the defeat of Delhi's last Hindu kingdom. The tower has five distinct 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. It is part of the Qutab complex, a UNESCO World Heritage Site.