The Detroit-Windsor Tunnel is approximately one mile long from portal to portal. The American portal is located a few hundred feet from Downtown Detroit while the Canadian end is located in the heart of Windsor's business district. Promotion of the Tunnel started over 120 years ago. The Tunnel was the first vehicular subway ever built between two nations. At the time of its construction two other tunnels were in use in the United States - the Holland Tunnel in New York and the George A. Posey Tunnel connecting Oakland and Alameda, California.