Nearby park with hiking trails. Park is broken up into multiple sections with lots to explore!
The Baltimore Aquarium is famous! Stop by to see the fish and have a meal in the inner-harbor after.
Camden Yards is fun to walk around even if there is no baseball at the time.
The nation's capital is a short ~40 minute drive south from Baltimore or 30 minutes from Columbia. There are many museums, restaurants, and government buildings to see.