Bash Tapia Castle, Medieval fortress on the Tigris River in Mosul, Iraq.

Bash Tapia Castle is a ruined fortress on the western bank of the Tigris in Mosul, built in the 12th century as one of seven castles in the city wall. Its surviving parts include a tall tower, rooms, a stronghold, storerooms and underground tunnels linking it to the old city.

The fortress was built in the 12th century as one of seven fortifications protecting Mosul. It suffered damage from Timur's attack in 1393 and was later restored during Ottoman-Persian conflicts.

The name Bash Tapia comes from Turkish, combining baş (main) and tabya (tower or bastion), meaning the main tower. The castle stands at the highest point of old Mosul, about 75 feet above ground level on the landward side and 150 feet above the Tigris. Its underground tunnels once linked it to the old city, and it was long popular with visitors from Turkey.

Access to the fortress may be limited and it is wise to check local conditions before visiting. The stone walls and uneven surfaces require appropriate footwear and caution when exploring.

Parts of the original medieval stonework survive despite severe damage in recent years. The visible stone blocks demonstrate the quality of the original craftsmanship and durability.