The stone tower, which was built in 1300, remained undamaged by the blaze. It’s known as the Wasserturm (“water tower”), not because it’s a pumping station, but simply because it’s standing in water. Notice that it sits on the side of the bridge that fronts the lake. That’s because enemy attacks usually came from Lake Luzern, which empties into the Reuss River at this point. As part of the Medieval defense system, the tower also acted as a prison and torture chamber.