For a time, the biggest was the Washburn A, which began production in 1880 and was able to grind enough flour to bake 12 million loaves of bread a day. But advances in technology eliminated dependence on waterpower and the giant mills by the Mississippi fell into disuse. The Washburn A was shut down in 1965 and sat empty and unused until it was nearly destroyed by fire in 1991.
The Minnesota Historical Society, a nonprofit organization, saw potential in the rubble, stabilized the ruins, and opened the award-winning museum a dozen years later, leaving many features of the original mill intact. Visitors can stop by the Baking Lab, board the Flour Tower elevator ride and take in the view from 110 feet up on the observation deck. But they won’t be able to see the last operating water-powered mill in the state, 150 miles to the south.
Correction: An earlier version of this article incorrectly identified the organization behind the museum. It is the Minnesota Historical Society, not the city of Minneapolis.