The Mackinac Bridge is Michigan's five-mile 'Mighty Mac.' Every day, only cars are allowed on it. Except one: every Labor Day, Michigan closes it to cars and opens it to walkers. The first walk, in 1958, drew just 68 people. For decades, two lanes stayed open to cars during the walk. Since 2017, all of them close, and walkers get the whole bridge to themselves. Now 40,000 to 65,000 show up every year, with a record 85,000 in one morning.
