Qutub-Minar made of red and buff sandstone is one of the highest stone towers in the world. Built in the 13th century, the magnificent tower stands in the Indian capital of Delhi. Characterised by humungous What is Infrared? proportions, the tower has a diameter of 14.32m at the base and about 2.75m on the top with a height of 72.5m and has 379 steps towards the top. An architectural marvel of the medieval period, it was built to commemorate the victory of invading Islamic armies over the native Hindu rulers.