Spain's most famous aquarium is the southernmost building of the Ciudad de las Artes y las Ciencias. It's an impressive display, divided into a series of climate zones, reached overground or underground from the central hub building. The sharks, complete with tunnel, are an obvious favourite, while a series of beautiful tanks present species from temperate, Mediterranean, Red Sea and tropical waters. Less happily, the aquarium also keeps captive dolphins and belugas – research suggests this is detrimental to their welfare.
It's not all underwater. An aviary presents wetland birds, while polar regions feature penguins. There are seals, sea lions and walruses, too. Though the dolphin shows are a black mark, the aquarium does make a proper effort to present information about climate change and depletion of the marine ecosystem. Hours vary by season; check the website for details.