A course allowing an optimal discovery of the masterpiece of Vauban, including the first underground gallery on the site, called "Communication 110", open to the public. Hours of operation : Monday May 01: 15:00:00 at 16:15:00: Wednesday July 12: 15:30:00 at 16:45:00 Monday May 08: 15:00:00 at 16:15:00:00 Sunday June 11: 3:00:00:00 PM at 16:15:00 Wednesday August 16: 15:30:00 at 16:45:00 Sunday, May 14: 3:00:00:00 PM at 16:15:00: Sunday May 21: 3:00:00 PM at 16:15:00: