Notre Dame is open to the public for both visiting and for silent prayer. It is very dark inside, except for the mostly dim illumination from the stained glass windows. The cathedral itself is free to visit, but for a small fee you can also climb the 387 steps up a very narrow, spiral staircase which leads to the top. There, you can walk across the front balcony which is located at the base of the two bell towers and is decorated by gargoyles. You can also go up inside one of the bell towers.