Caverne de Saint-Léonard

Beneath Pie-XII Park, a concrete stairway and a steel gate open onto a fissure in Ordovician limestone 450 million years old, widened by the pressure of ice some 15,000 years ago. Spotted around 1812 and long nicknamed the *Fairy Hole*, the cavity is said to have hidden weapons for the Patriotes in 1837, before being sealed in 1968.