The Alai Darwaza is the main gateway from southern side of the Quwwat-ul-Islam Mosque. It was built by the second Khilji Sultan of Delhi, Ala-ud-din Khilji in 1311 AD, The domed gateway is decorated with red sandstone and inlaid white marble decorations, inscriptions in Naskh script, latticed stone screens and showcases the remarkable craftsmanship of the Turkic artisans who worked on it.