The Straits of Mackinac Shipwreck Preserve are divided in two by a bridge spanning how long?
Mackinac Bridge The Mackinac Bridge ( ) is a suspension bridge spanning the Straits of Mackinac to connect the Upper and Lower Peninsulas of the U.S. state of Michigan. Opened in 1957, the 26372 ft bridge (familiarly known as "Big Mac" and "Mighty Mac") is the world's 19th-longest main span and the longest suspension bridge between anchorages in the Western Hemisphere. The Mackinac Bridge is part of Interstate 75 and the Lakes Michigan and Huron components of the Great Lakes Circle Tours 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 on the north end with the village of Mackinaw City on the south.
Marquette Underwater Preserve The Marquette Underwater Preserve was established in 1990 to promote conservation of the submerged historical resources in Lake Superior near Marquette, Michigan. The Preserve is composed of two separate units, the Marquette Unit and the Huron Islands Unit. The Marquette Unit extends along approximately 24 miles of Michigan shoreline out to the 200-foot depth contour. The Huron Islands Unit surrounds a group of granite peaks about 12 miles from shore. The Michigan Underwater Preserve Council oversees activities relating to all of Michigan's Underwater Preserves.