Archaeological site Grotte de Spy in Jemeppe-sur-Sambre

You're standing at Spy Cave, high on a hillside above the left bank of the Orneau, a small tributary of the Sambre. You're about twenty metres above the water, and that's no accident. After the Ice Age the water still reached this high, and it carved this hollow out of the limestone. Take a look at the opening. Behind the main chamber, smaller rooms and corridors branch off to the right and above. In front lies a terrace, and the slopes below it are largely rubble dumped by earlier digs.