The National Aquarium in Baltimore, Maryland is a fantastic place to visit.
Since it is an aquarium, there were tons of different types of fish and sealife, including sharks, stingrays, and turtles. The aquarium is set up so that you can really get up close and personal with all the sea life.
My favorite area of the aquarium is the Australian exhibit. As you walk through, it truly feels as though you are actually in Australia. I especially loved the variety of turtles in this exhibit.
The aquarium also has a Tropical Rain Forest exhibit with birds and monkeys, etc.
Another favorite part of the aquarium was the Dolphin Show in the Marine Mammal Pavilion. Although you pay extra to see the show, it's worth it to see these beautiful animals up close. The show centers a lot around how they train the dolphins to do tricks through playing...very cool.
The National Aquarium in Baltimore is located conveniently in the Inner Harbor, so if you are visiting Baltimore, this is a must see. Enjoy!