Austria's family activity infrastructure is exceptional in both quality and variety. The Vienna Natural History Museum has one of the world's most significant dinosaur fossil collections alongside the Venus of Willendorf — a 30,000-year-old figurine that children find fascinating for its age alone. The Vienna Prater Riesenrad, the 1897 giant Ferris wheel, gives children a historical fairground experience and a city panorama. The Haus der Musik sound museum is specifically designed for multi-age interactive engagement with music physics and the history of Vienna's composers. Innsbruck's Alpenzoo, at 727 metres above the city, has the highest altitude collection of Alpine animals in the world. The Swarovski Crystal Worlds in Wattens, near Innsbruck, has a specifically designed children's dream landscape among its installations. The Hallstatt salt mine — the world's oldest, accessible by underground slide — is a child-friendly heritage experience of genuine geological and industrial depth.