These caves are old marl quarries which were used in Roman times. They often served as a sanctuary for refugees (French Revolution, the wars). The sedimentary rock contains many fossils. The walls are covered with drawings in charcoal or in bas-reliefs, the former depicting animals of which fossils have been found (mosasaurus), others on artistic (Joconde) or religious subjects.

This "hell's gate", flanked by two round towers is a remnant of the 13C surrounding wall. This is the oldest town gate in the Netherlands.

Located in a large hangar, this museum has reconditioned tramways and buses. For adults as well as children.

This flamboyant Gothic church retains a Romanesque narthex, the remains of the Benedictine abbey founded in the 11C. To the north, you will see an interesting Renaissance façade. Under the porch, a bas-relief from 1380 represents the coronation of the Holy Virgin. The vaults of the nave have many quite spectacular ribs. The choir has an ogival flamboyant style of incredible richness.