The Detroit-Windsor Tunnel - Detroit, Michigan - underwater border crossing into Canada from Michigan

The Detroit-Windsor tunnel is one of the busiest and most important border crossings between the United States and Canada. It also has the distinction of being the only vehicular underwater border crossing between two countries anywhere in the world. An estimated 28,000 vehicles take the mile long trip under the Detroit River every day, which means around 9 million vehicles cross into Canada or the United States at this location every year.

As far back as 1870, Detroit engineers were considering a tunnel or a bridge to link the cities of Detroit and Windsor. Several attempts to build a tunnel were actually made in the late 19th century; all were abandoned for various reasons, including prohibitive costs and the discovery of harmful gases. The growth of the car industry in the early 20th century made it clear that a tunnel for road traffic was necessary.

Construction proper began on the tunnel in 1928, after sufficient funding was made available by a group of Detroit bankers and a New York architectural firm verified that the tunnel would be both possible and profitable. Work commenced on both the US and the Canadian ends of the tunnel simultaneously using several different methods - a major engineering feat at the time. Construction also involved the difficult task of sinking nine steel tubes into a trench in the riverbed.

The tunnel cost of around 23 million dollars and was completed in 1930, a year ahead of schedule. President Hoover dedicated the tunnel on November 1st 1930, in a ceremony from Washington that rang bells in both Detroit and Windsor to officially declare the tunnel open. Two days later, on November 3rd, 1930, the first cars made their way through the tunnel.

One of the most impressive features of the tunnel is its innovative system to pump fresh air in to the tunnel; in fact the air inside is cleaner than the air at street level. Tall ventilation towers at both ends of the tunnel contain huge fans and are each responsible for ventilating half of the tunnel. The system is so effective that the air in the tunnel is changed completely every 90 seconds.

Apart from the volume of traffic that it handles, the tunnel's other statistics are just as impressive. During its construction, an estimated 80,000 cubic yards of concrete were used, as well as almost 12,000 tons of steel and 50 miles of electrical cables. The interior of the tunnel is illuminated by almost 600 lights and contains 250,000 wall tiles. At any one time, up to 600 laborers worked on its construction.

Today, the Detroit-Windsor Tunnel provides a fast and convenient link between the US and Canada. The tunnel is jointly owned by both cities and efforts are continually being made to improve the overall travel experience. In 1993, a major renovation program costing $50 million was launched; work included improvements to lighting, the road surface and the stone covering. Current improvements are concentrating on allowing customers to pay the toll electronically, thus reducing wait times at the tolls and helping to improve traffic flow.