Consecrated in 1046, the abbey church has two transepts and two opposing choirs. The late-Romanesque west end or "Westbau" is laid out over five levels. Inside, the church is striking for its dimensions and simplicity; note the gracious 15C polychrome wood statue of the Virgin of the Annunciation. In the east choir a 16C coffer chest marks St Gertrude's tomb. Under the west choir the 11C crypt was the focal point for pilgrims. Archaeologists found five earlier churches here; fine 13C cloister.