Qutb Minar
The Qutb Minar ("Tower of Victory") was begun in 1199 by Qutb ud-din Aibak, founder of the Delhi Sultanate. At 240 feet it is one of the tallest brick-built towers in the world and is thought to have been primarily built for defense and reconnaissance, as well as a symbol of victory over the vanquished locals. The tower has five distinct sections, each with a different shape; the uppermost one was damaged and rebuilt in the 1300s.
Near the tower Aibak also built a mosque (India's first), for which he re-used pillars from destroyed Hindu and Jain temples . Earthquakes through the centuries have damaged most of the buildings, but the tower has stayed intact. The interior stairway has 379 steps to the top, but has has been closed to the public since a despondent Indian teenager chose it as a suicide spot in 1985.
As an early Islamic settlement site, this was a natural spot for Muslims to build a madrasa (Islamic legal school). It also contains several tombs, including that Iltutmish, the third ruler of the Delhi sultanate and the first to rule from Delhi (the earlier ones were based in Lahore in Pakistan).
The complex is small but quite beautiful, and an extremely popular Sunday outing for Delhi families.