Sitting alone in a rocky, sandy expanse of desert in the municipality of Madinat ash Shamal in Qatar, this beautifully preserved fort was built in the early 1800s out of rough blocks of coral, limestone and mud. Thaqab means 'water in the bottom of the valley after the rain' and is widely believed to have been built to guard water – a most precious commodity in the desert - which came from a deep well on the west side of the fort.