Inside view of Detroit-Windsor Tunnel, no vehicles visible. Tiled walls; walkway along road. Printed on front: "4. Detroit-Windsor tunnel. 1A1172." Printed on back: "The Detroit-Windsor tunnel is 5,135 feet in length and cost $25,000,000. It required 2 1/2 years to complete same. The top of the tunnel is 45 feet and the roadway 75 feet underwater. It required 80,000 cubic feet of concrete, 11,000 tons of structural and 750 tons of reenforcing steel. 20,000 granite blocks were used in building the roadway. Capacity is 2000 cars per hour. C.T. American Art Colored. C.T. Co., Chicago."
Burton Historical Collection, Detroit Public Library