Giessen

Giessen is town in central Germany, north of Frankfurt. It's known for the Mathematikum, a museum focused on math, with hands-on experiments. Next door, the Liebig Museum has chemistry exhibits, plus the lab of 19th-century scientist Justus von Liebig. Part of the University of Giessen, the Botanical Garden was founded in 1609 and has thousands of plant species. Northwest, Burg Gleiberg castle overlooks the town.