White Shoal Light, an active lighthouse in Lake Michigan west of the Mackinac Bridge, was built from 1908 to 1910 on an isolated shoal as part of the United States Lighthouse Board’s effort to replace exposed lightships with permanent offshore structures. The tallest lighthouse on the Great Lakes, it guided ships through the dangerous waters near the Straits of Mackinac with a powerful Fresnel lens, fog signals, and a submersible bell. Praised as a major engineering achievement, it is especially famous for its red-and-white spiral daymark, aluminum-topped lantern, and enduring place as one of Michigan’s most recognizable lighthouse landmarks.