Winding Ice Age Cave Discovered Beneath Montreal

The cave stretches for more than 600 feet and splinters off into a number of different passageways

Luc Le Blanc

Montreal is a beautiful and bustling place, filled with restaurants, shops and the best bagels in the world (sorry, New York). As Jaela Bernstien reports for CBC News, something just as marvelous lies beneath the city’s streets: an Ice Age chamber that stretches for more than 600 feet.

The hidden passage was recently discovered by two amateur spelunkers, Luc Le Blanc and Daniel Caron. For years, the friends had been exploring a small underground cave, the Saint-Léonard cavern, that was discovered in 1812. They believed that a hidden passageway might lie beyond the cavern’s walls and in October of this year, their hunch was confirmed.

"This is a major discovery we made," Le Blanc tells Bernstein. "This doesn't happen many times in a lifetime."

According to Ashifa Kassam of the Guardian, Le Blanc and Caron relied on dowsing, a centuries-old technique that is sometimes used to locate groundwater, to detect an anomaly in the ground of the Saint-Léonard cave. In 2015, they were able to push a camera through a small fissure at the end of the cave, and the resulting images suggested that the passage extended even further. In October, following a failed attempt to drill through the limestone wall, Le Blanc and Caron hit upon a soft layer of rock that allowed them to carve a small window into the cavern.

What they found beyond the walls of the Saint-Léonard cavern astonished them. “It’s just beautiful,” Le Blanc says of the newly discovered chamber, according to Kassam. “The walls sometimes look like layers of fudge and chocolate; there’s brown, there’s dark brown, there’s ochre.”

The cave splinters off into a number of different passageways, reports Morgan Lowrie of the Canadian Press. Stalactites hang from the ceiling, which stands at about 20 feet high. Because the cave reaches an aquifer, it is filled with clear waters; in some passages, the water reaches a depth of around 16 feet. The explorers had to use a canoe to navigate the cave, but Le Blanc tells Bernstien of CBC News that they “haven't reached the end yet.”

The cave was formed around 15,000 years ago, when pressure from a huge glacier split the rock beneath it. For centuries, however, the residents of Montreal did not know that a hidden world lay under their feet.

“They built the street over the cave and they never found the cave,” says François Gelinas, the director of Quebec’s speleological society, according to Lowrie.

The city has commissioned a study of the cave and reportedly plans to one day open it to the public.

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