Built in 1888, this palatial building has a deep-eyed bust of Darwin on its central pediment, best spotted from the river-ferry as it approaches the Pôle Fluviale jetty. Even if your French isn't sufficient to warrant visiting the building's two educational museums, it's still worth nipping inside the foyer to admire Genesis, a remarkable 1960 mural by celebrated Belgian artist Paul Delvaux.
If you have more time, the new science museum has several interactive experiences good for inspiring youngsters about physics, and it's free for children. The 'Aquarium' goes beyond fish and displays a major zoological collection and hosts exhibitions. However, neither have much that's in English. Hidden in the grounds behind, fascinating Labo4 has very originally recycled a 1963 university laboratory into a quality restaurant.