This mammoth oceanfront museum was founded by Albert I, great-grandfather of the present prince, in 1910. It’s now a living, breathing science lesson covering the world’s oceans by way of a Mediterranean aquarium, tropical tanks, and a shark reserve. A delight for budding marine scientists is the 18m-long (60-ft.) whale skeleton that washed up on a local beach a century ago. Equally as compelling are the scientific specimens brought up from the ocean depths over the past 100 years. Princess Charlene hosted the third birthday party of twins Jacques and Gabriella here in 2017. Be aware that during the wintry low season (through most of Nov until Mar), entry prices are reduced by 5€.