INNER HARBOR. One of the best, if not THE best, aquariums in the country. Laid out perfectly, this museum actually lets you touch living creatures. Upon entering the large foyer, you will notice a four-story tank holding a multitude of marine life. Start on the fourth floor in the rainforest exhibit and then walk down a spiral ramp that intersects the doughnut-shaped tank. Don't forget to view the sea lion pool outside the aquarium or the Marine Mammal Pavilion, which houses bottle-nose dolphins. Located along the harbor, the seven-story glass structure is easy to spot.