You Can Drive Underwater Into Another Country — Only in Detroit

Here’s a Michigan oddity you can experience for yourself. You can get in your car in downtown Detroit, drive down into a tile-lined tube, pass beneath a river, and come up in another country. The Detroit–Windsor Tunnel is the only place in the world where you can drive underwater across an international border.

It opened to traffic just after midnight on November 3, 1930, linking downtown Detroit with downtown Windsor, Ontario. Before it (and the Ambassador Bridge a year earlier), cars crossed the Detroit River by ferry. The tunnel runs about 5,160 feet — nearly a mile — and at its lowest point sits roughly 75 feet beneath the river’s surface.

Building it was a feat. Engineers used an “immersed tube” method: long steel tube sections were built in dry docks, floated out, sunk into a trench dredged in the riverbed, joined together, then sealed and paved. The first car through was a 1929 Studebaker. At the grand opening, President Herbert Hoover turned a “golden key” in Washington that set bells ringing on both sides of the border.

Today the tunnel still carries around 12,000 vehicles a day — roughly four million a year — between the two downtowns. A powerful ventilation system pushes well over a million cubic feet of fresh air through it every minute, swapping out the air about every minute and a half. It’s the second-busiest crossing between the U.S. and Canada, just behind the nearby Ambassador Bridge.

If you go, bring your passport — it’s a real border. But few border crossings come with a story this good: a quick, quiet drive beneath a river, from one country into the next.