Round Tower, Fortified tower in Andernach, Germany.

The Round Tower in Andernach is a fortified tower with a circular base and an octagonal upper section that rose above most other structures when first built. The stone construction displays the military architecture of the 15th century with its solid walls and narrow defensive openings.

The Round Tower was built by the citizens of Andernach between 1412 and 1453 as a civic counterweight to the archbishop's castle, deliberately funded without a contribution from Cologne Archbishop Dietrich II of Moers. Its base held a prison called the "deustere kamer"; the nobleman Gerlach Hausmann von Namedy was imprisoned there in 1509. In 1689 the tower withstood a French attempt to blow it up, leaving a 1.2-metre breach on its west side.

The tower represents the city's determination to assert its independence from religious authorities of that era. Visitors today recognize it as a defining landmark of the medieval old town and use it as a reference point while exploring the historic streets.

The tower is located in Andernach's old town and can easily be reached from Cologne Street in the city center. It works well as a reference point while walking through the medieval streets of the historic district.

In the night of 30 April to 1 May 1689, the tower withstood an attempt by retreating French troops of Louis XIV to blow it up. What remains is a breach about 1.20 metres deep on the western field side, roughly the size of a small car.