Some of Canada’s most interesting history isn’t visible from the street. It survives beneath cities, military sites, and former industrial areas.
1. Toronto’s Old Tunnels
Toronto has layers of underground infrastructure, from historic tunnels to the modern PATH network.
Heritage Toronto notes that the downtown PATH system alone stretches roughly 30 kilometres beneath the city.
2. The Diefenbunker
Outside Ottawa, an enormous four-storey bunker was built underground during the Cold War to protect Canada’s political and military leadership from a nuclear attack.
It operated from 1961 to 1994 and is now a national historic site and museum.
3. North Bay’s Underground Bunker
Deep beneath the Canadian Shield near North Bay sits a Cold War air-defence complex.
The cavern system was blasted roughly 600 feet underground and formed part of Canada’s participation in NORAD.
4. The GECO Tunnels in Scarborough
During World War II, a huge munitions factory operated in Scarborough.
More than four kilometres of tunnels carried electricity, water, steam, and compressed air beneath the top-secret facility, which produced more than 256 million munitions.
5. The St. Clair Railway Tunnel
Built between 1889 and 1891 beneath the St. Clair River, this tunnel connected Canada’s railway network with the United States.
At 1,837 metres long, it was considered one of the great engineering achievements of its era.
6. Canada’s Future Nuclear-Waste Repository
Some of Canada’s most important underground infrastructure is still being planned.
A proposed repository in northwestern Ontario would place used nuclear fuel in tunnels and storage rooms 650 to 800 metres underground.
Much of Canada’s history—and some of its future—exists below ground, hidden beneath places millions of people pass every day.