With freshwater rivers and salt marshes, deep oceans and family activities, the St. Louis Aquarium is a fun and educational experience inside St. Louis Union Station.  There are 13,000 animals including 257 species located within the Aquarium, covering 120,000 square feet.  There are six themed galleries at the Aquarium including the Confluence Gallery which teaches visitors about rivers and the animals that are important to this region.  Or, Visit the Deep features bioluminescent animals in addition to an octopus and sea dragons.  The Aquarium is also famous for its sharks, from sandbar sharks to lesser devil rays.  Tickets can be purchased online, and it is recommended to purchase them in advance.