The Qutb Minar also spelled as Qutab Minar or Qutub Minar, is a minaret that forms part of the Qutb complex, a UNESCO World Heritage Site in the Mehrauli area of Delhi, India. Qutb Minar is a 73-meter (239.5 feet) tall tapering tower of five stories, with a 14.3 meters (47 feet) base diameter, reducing to 2.7 meters (9 feet) at the top of the peak. It contains a spiral staircase of 379 steps. Its design is thought to have been based on the Minaret of Jam, in western Afghanistan.
Qutb-ud Din Aibak, the founder of the Delhi Sultanate, started construction of the Qutb Minar's first story around 1192. In 1220, Aibak's successor and son-in-law Shamsuddin Iltutmish completed a further three storeys. In 1369, a lightning strike destroyed the top storey. Firoz Shah Tughlaq replaced the damaged story and added one more. Sher Shah Suri also added an entrance to this tower while he was ruling and Humayun was in exile.