POTATO CAVE

It was discovered in 1980, not far from the river of the same name, and its formation also dates back to the last Ice Age. Its dimensions are truly impressive: 10 metres high at the entrance, 7 metres wide and 80 metres long, with a 625-metre-long gallery that narrows progressively. In fact, it's one of the longest underground cavities in Quebec. To explore its depths, safety helmets and headlamps are a must (available for hire from McDonald's Service Center).