L'Oceanogràfic opened its doors in 2003, and was an immediate hit. The price of entrance isn't cheap, but you could easily spend all day here. And you'll need to, if you plan on seeing everything. This is the largest oceanarium in Europe, with sections dedicated to the Red Sea, the Arctic, the Mediterranean, coral reefs, mangrove forests, tropical waters and the oceans. There's an auditorium, a dolphinarium, a spherical bird sanctuary and multiple restaurants. Grumble about the ticket price all you want, but by the end of the day it's hard to deny you got your money's worth.