Tughlaqabad Fort is a ruined (collapsed or broken) fort in Delhi. It was built by Ghiyas-ud-din Tughlaq in 1321. He was the founder of Tughlaq dynasty of the Delhi Sultanate of India. Ghiyasuddin established (built) the third historic city of Delhi, the Tughlaqabad. This fort was built in Tughlaqabad. This city was later abandoned (left) in 1327.