Haus Ruhrnatur

Life in and along the River Ruhr is the theme here: local fish, tiny creatures under the microscope, and the sounds and smells of the river. Its 32 hands-on stations include a flow model, a water-drop marble run and the three-metre-high Ruhr aquarium holding 4,000 litres. Visitors can also experiment with wind wheels, water turbines and solar collectors. The building on the lock island was put up in 1926 as a school boathouse.