When Louis the 14th, French Emperor took over Ypres, his architect Vauban, build a fortress and a large moat around the city to make it invincible. This incredibly ingenious contruction had such thick walls, that even the German artillery during the first world war had difficulties in destroying it. They destroyed the inner city with bombardments, but the fortress remained more or less intact. Inside the fortress lays a complex of chambers, the “Kazematten”, where also during the 1st world war, soldiers took refuge. The Rijsel gate was one of the entrance gates to the inner city at the time of Louis the 14th.
