Opened in 2013, this glass-and-metal starfish-shaped building perches in a sublime position on the Qawra headland, with endless blue views. It's great fun, with huge tanks showing environments that mimic the waters around the islands (for example, there's a replica of the bronze submerged Christ of the Abyss statue), as well as those further afield. There's a 12m underwater tunnel that allows visitors to walk through a huge tank, as well as another smaller tunnel to crawl through.
Daily educational sessions include learning about marine evolution and the aquarium's shark conservation program. Check the website for timings. The complex includes a children's playground (free of charge) and stunning views from its La Nave restaurant and outdoor cafe.