Prepare to be wowed at the Aquarium de San Sebastián, the first natural science museum ever built in Spain. Not just one of the most modern aquariums in Europe after its recent renovations and extension, it contains over 5,000 species of fish, many of them local species, as well as an auditorium with a giant fish tank for a screen. The aquarium's biggest attraction is, however, a 360° panoramic underwater tunnel where you can walk through and admire sharks, stingrays and other sea creatures with the fish all around you. It is also an oceonagraphy museum looking at the seafaring history of the Basque country with fantastic, historically accurate, ship models, and an 11m long skeleton of a North Atlantic right whale.