<P> The Qutub Minar, also spelled as Qutab Minar, or Qutb Minar, is the tallest minaret in the world made up of bricks . The minaret forms a part of the Qutab complex, a UNESCO World Heritage Site in the Mehrauli area of Delhi, India . Qutub Minar is a 73 - metre (239.5 feet) tall tapering tower of five storeys, with a 14.3 metres (47 feet) base diameter, reducing to 2.7 metres (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 . </P> <P> Qutab - Ud - Din - Aibak, founder of the Delhi Sultanate, started construction of the Qutub Minar's first storey 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 storey, and added one more . Sher Shah Suri also added an entrance to this tower while he was ruling and Humayun was in exile . </P> <P> The Minar is surrounded by several historically significant monuments of the Qutab complex, including Quwat - ul - Islam Mosque, which was built at the same time as the Minar, and the much older Iron Pillar of Delhi . The nearby pillared Cupola known as "Smith's Folly" is a remnant of the tower's 19th century restoration, which included an ill - advised attempt to add some more stories . </P> <P> Qutab Minar was established along with Quwwat - ul - Islam Mosque around 1192 by Qutab - ud - din Aibak, first ruler of the Delhi Sultanate . The mosque complex is one of the earliest that survives in the Indian subcontinent . The minaret is named after Qutab - ud - din Aibak, or Qutbuddin Bakhtiar Kaki, a Sufi saint . Its ground storey was built over the ruins of the Lal Kot, the citadel of Dhillika . Aibak's successor Iltutmish added three more storeys . The minar's topmost storey was damaged by lightning in 1369 and was rebuilt by Firuz Shah Tughlaq, who added another storey . In 1505, an earthquake damaged Qutub Minar; it was repaired by Sikander Lodi . On 1 September 1803, a major earthquake caused serious damage . Major Robert Smith of the British Indian Army renovated the tower in 1828 and installed a pillared cupola over the fifth story, thus creating a sixth . The cupola was taken down in 1848, under instructions from The Viscount Hardinge, then Governor General of India . It was reinstalled at ground level to the east of Qutab Minar, where it remains . It is known as "Smith's Folly". </P>

Who were involved in the building of qutub minar