Ancient Tughlaqabad Fort in Delhi, India

Tughlaqabad Fort, now in ruins, is an amazing site to visit in Delhi, India. It is a large sprawling fortress stretching over 3.5 miles (6 km). It was built by Ghiyas-ud-din Tughlaq, founder of Tughlaq dynasty, in 1321. This considered the third historic city of Delhi, that was later abandoned in 1327. It's hard to believe it was abandoned with all the hard work that went into it.