Contributor Shazar created this amazing drone video of one of the world's largest fortresses. Ranikot Fort is located in the state of Sindh in southern Pakistan. The location is was known to be fortified as early as the Antiquity. The current fortress structure dates to the 16th century. Ranikot's walls run a total of 32 km (about 20 mi), making it the largest fortress in the world measured by interior space. Built by the Talpur tribe, the fortress came under control of the British Empire in the 18th century.