St. Gereon's Basilica

St. Gereon's Basilica is a Romanesque and Gothic structure in Cologne's Altstadt-Nord district, known for its ten-sided central hall and two western towers. The interior halls and chambers display elaborate marble decorations throughout, defining the character of the entire building.

The original oval building dates from the fourth century, making it one of Germany's oldest remaining sacred structures at its original location. Over the centuries, the building was expanded and redesigned multiple times, with the Romanesque and Gothic phases being particularly formative.

The marble high altar displays black and white patterns with gold applications, representing centuries of religious craftsmanship and artistic dedication. This decoration combines Roman material tradition with medieval color symbolism in a way that visitors can still perceive directly today.

The church is accessible Monday through Saturday from 9:00 to 12:30, and Monday through Friday plus Sunday from 13:30 to 18:00. Visitors should note the midday break and plan accordingly to make use of both visiting windows.

The central dome structure stands as the largest self-supporting building of its kind north of the Alps, measuring 79 by 62 feet (24 by 19 meters). This technical achievement from antiquity was realized without modern aids and still impresses architects and engineers today.