Immediately above and to either side of the main entrance, the building rises slightly higher than the rest of the main structure, forming two guard towers flanking a central structure on the left and right. This design emphasizes the importance of the Main Entrance and highlights the grandeur of the central tower.

The guard towers were damaged in bombing during World War II. When they were later repaired, the original half-domed roofs were replaced by the flat roofs of today.