Sankt Gerebernus, Medieval pilgrimage chapel in Sonsbeck, Germany.

Sankt Gerebernus is a chapel in Sonsbeck featuring three naves made of tuff stone, divided into four bays in the nave and one in the choir, all covered with mesh vaults. The structure displays typical medieval construction techniques found in regional churches from its period.

The chapel began as a court chapel around 900 and underwent expansion in 1478 to handle growing numbers of pilgrims. This transformation made it a significant stopping point for religious travelers in the region.

The chapel's name shifted over centuries: officially dedicated to St. Catherine in 1203, it was called St. Gerebernus by locals, shortened to "St. Gebern" or "St. Berem" in dialect, and sometimes corrupted to "St. Bernadus." Pope Leo X restored the official name St. Gerebernus, and from 1513 pilgrims received indulgences on feast days. A hermit's hut on the north side of the tower collected votive offerings of wax, iron and precious metals, sold for the church's benefit.

The chapel is open to visitors during daytime hours, and visits outside regular times can be arranged through the parish office. It is helpful to contact ahead, especially if you wish to visit at a specific time.

The chapel holds one of only two surviving Kriechaltäre (crawling altars) in Germany. Pilgrims squeezed through a tunnel in the altar block as penance, hoping for relief from gout, paralysis and epilepsy. Grooves worn by their wooden clogs are still visible in the stone floor.