The building work for this amazing feat of mediaeval engineering commenced in 1137. The objective was to drive a tunnel through the Münchsberg mountain to carry a canal to provide fresh water for the district of St. Peter. During the course of construction the engineers encountered many problems and as a result of these the canal winds its way erratically through the mountain. Amazingly the canal is till in use today except for a period in the autumn when it is drained for maintenance checks. Visitors can take a guided tour of the canal complex but should be aware that waterproof clothing is required.