Explorers Discover Massive, 15,000-Year-Old Cave Just Metres Below Montreal By Christian Nathler By Christian NathlerView Author|December 4, 2017|NewsView News Explorers made the discovery of a lifetime this weekend beneath the city of Montreal. As it turns out, a vast network of Ice Age-era caves and passages exists just 10 metres below the residential streets of Saint-Leonard in the city's East... View this article.