Aqualandia claims to be Europe's biggest water park, and it's huge. You can see it rising from the coastal plains long before you arrive, more than 20 enormous slides including the "Black Hole," a wet ride through the darkness, and the "Big Bang," the highest chute on the continent.
Younger swimmers can enjoy Adventureland, the best kiddie pool imaginable. There is also a wave pool, rapids, and plenty of playground equipment, restaurants, and shops on dry land. You could easily spend all day here, so don't forget your sunscreen.