Customs Tower (Rententurm), Frankfurt

The Customs Tower, also known as Rententurm, located in Frankfurt, stands as a testament to the city's rich history and architectural heritage. When you turn towards Römerberg, you'll notice this four-story building elegantly situated on your right corner. Built in 1456, the Customs Tower is a rare surviving example of late Gothic gate towers from Frankfurt's old city fortifications.

Today, the Customs Tower has been integrated into the Historische Museum Frankfurt, where it preserves and displays its historical significance. Its roots, however, trace back to a much earlier period, as it sits atop the foundation walls of the Kaiserpfalz, initially constructed by Emperor Friedrich Barbarossa in 1150.

The tower itself is an architectural masterpiece, built by the skilled hands of Eberhard Friedberger. It takes the form of a four-story gate tower on a square floorplan, complete with a pointed spire and four turrets, combining both strength and elegance.

The Customs Tower is closely connected to the Saalhof ensemble, once the Staufer imperial palace dating back to the 12th century. However, by the time the Rententurm was constructed, it had passed into private ownership. This multifaceted structure had a dual role, serving as a protective military outpost guarding the city gate (Fahrtor) and as the place for collecting tolls and port charges. Interestingly, the tower's basement even served as the city prison, occasionally facing flooding when the Main River surged.