Qutub Minar is a minaret or a victory tower located in Qutub complex, a UNESCO World Heritage Site in Delhi's Mehrauli area. With the height of 72.5 metres (238 ft), Qutub Minar is the second tallest monument of Delhi. Its construction was started in 1192 by Qutb Ud-Din-Aibak, founder of Delhi Sultanate after he defeated the last Hindu Ruler of Delhi. He constructed the basement, after which the construction was taken over by his son-in-law and successor Iltutmish who constructed three additional stories. The fourth and fifth storeys were built by Firoz Shah Tuglak.