Wikipedia
Mathematikum
The Mathematikum is a science museum, located in Gießen, Germany, which offers a huge variety of mathematical hands-on exhibits. It was founded by Albrecht Beutelspacher, a German mathematician.
The Mathematikum opened its doors to visitors on 19 November 2002. It was inaugurated by the German president Johannes Rau. Since then, the museum has attracted more than 1,500,000 visitors. Annually the museum is visited by more than 150,000 people. The museum is opened every day of the week, including Sunday and Monday.