The Mackinac Bridge, the world's longest suspension bridge between anchorages at the time, opens to traffic connecting Michigan's upper and lower peninsulas.

The Mackinac Bridge is a suspension bridge that connects the Upper and Lower peninsulas of the U.S. state of Michigan. It spans the Straits of Mackinac, a body of water connecting Lake Michigan and Lake Huron, two of the Great Lakes. Opened in 1957, the 26,372-foot-long bridge is the world's 27th-longest main span and is the longest suspension bridge between anchorages in the Western Hemisphere. The Mackinac Bridge is part of Interstate 75 (I-75) and carries the Lake Michigan and Huron components of the Great Lakes Circle Tour across the straits; it is also a segment of the U.S. North Country National Scenic Trail. The bridge connects the city of St. Ignace to the north with the village of Mackinaw City to the south.