We visited the Stewart Museum on Ile Sainte Helene, which at one time was a prison camp during World War II. It is a fortification on the Saint Lawrence River that served as an arsenal for military weapons and equipment originaly built between 1820 - 1824. Very interesting artifacts on display, there are three floors, and the main entrance is a glass tower. If you go to the top of the stairs in the glass tower you have a great view of Montreal and the surrounding area. One of the photos within the building shows a cobblestone road beneath a glass floor with the rails that carried the munitions.