The name of this impasse (dead end) goes back to the congregation of the Ursulines, whose 17th-century monastery is still partly visible at the bottom of the Montagne-de-Bueren staircase. It appears as a kind of small maze with alleyways that climb the hill of the citadel parallel to the staircase. With walls that support cloisters and living quarters, traces of ancient constructions are still visible.