Cincinnati Triple Steam

These four massive steam-powered water pumps are the largest in the world and were state-of-the-art in 1906, when they started a 57-year career delivering water for the Greater Cincinnati Water Works. They remain large and impressive engineering artifacts, and the tour is fascinating. The route is somewhat wheelchair accessible, and no children under age 7 are permitted. There are several other restrictions; see the tour website. Admission is only possible with a guided tour, and the tours are scheduled when enough people sign up on a wait-list.