On this day in 1930, President Herbert Hoover turns a telegraphic "golden key" in the White House to mark the opening of the 5,160-foot-long Detroit-Windsor Tunnel between the U.S. city of Detroit, Michigan, and the Canadian city of Windsor, Ontario. The tunnel opened to regular traffic on November 3. The first passenger car it carried was a 1929 Studebaker.
Since the beginning of the 19th century, Detroiters and Windsorians had been trying to find a way to move people and goods back and forth across the Detroit River. For decades, railroad interests proposed tunnels and bridges galore, but powerful advocates of marine shipping always managed to block those projects: They did not want to lose business to faster and more capacious trains. (Plans for bridges were particularly troubling to those shippers, since just one low-hanging over-the-water crossing had the potential to keep high-masted sailing vessels off the river altogether.)
In 1871, the region's railroads finally won permission to build a trans-national tunnel, and workers began to dig into the river at the foot of Detroit's San Antoine Street; however, they were forced to abandon the project just 135 feet under the river when they struck a pocket of sulfurous gas that made workers so ill that none could be persuaded to return. Likewise, in 1879, another tunnel had to be abandoned when it ran right into some unexpectedly difficult to excavate limestone under the river. The first successful Michigan-to-Canada tunnel project finally opened in 1891: the 6,000-foot-long Grand Trunk Railway Tunnel at Port Huron.
Soon enough, it was clear to most people on both sides of the border that they needed to build some sort of structure for transporting automobiles across the river. In June 1919, the mayors of Detroit and Windsor decided to build a city-to-city tunnel that would serve as a memorial to the American and Canadian soldiers who had died in World War I. Even after advocates of the under-construction Ambassador Bridge tried to frighten away the tunnel's backers, spreading rumors about the danger of subterranean carbon monoxide poisoning, tunnel boosters were undeterred. (They were, one said, "inspired by God to have this tunnel built.")
Construction began in 1928. First, barges dredged a 2,454-foot-long trench across the river; next, workers sank nine 8,000-ton steel-and-concrete tubes into the trench and welded them together. An elaborate ventilation system kept the air in the tunnel safe to breathe.
In the first nine weeks it was open, nearly 200,000 cars passed through the Detroit-Windsor Tunnel. Today, about 9 million vehicles use the tunnel each year.