Paris has many themed museums that go beyond the usual tourist circuits. The underground sewer system has been open for visits since the 19th century, allowing visitors to see the technical installations that revolutionized urban hygiene. The fan museum houses over 2,500 pieces from the Renaissance to today, explaining traditional manufacturing techniques. The counterfeiting museum compares authentic products with copies to highlight issues of intellectual property. The Parisian collections cover a variety of fields: Asian art at the Guimet Museum with 45,000 objects from the Neolithic to the 20th century, African and Oceanian cultures at Quai Branly, fairground artifacts from the 19th century at Arts Forains, old automata and magic devices from past centuries. The Museum of Hunting and Nature is housed in a 17th-century townhouse and combines antique weapons with modern designs. These institutions offer unique insights into the social, technical, and artistic history of Paris.