This gloriously solid behemoth on the Dniestr dates to the late 15th century and the reign of Moldavian Prince Ştefan cel Mare. It was built on the remains of a wooden fortress in the shape of a circle, with five bastions. Today those bastions contain medieval-themed exhibits, with a few English placards posted about that shed light on the history of the fortress.
From the eastern bastions you can watch a Soviet-era river ferry shuttle cars to Ukraine, two at a time. The fortress hosts a festival every August.