Independence National Historical Park,
See America's second birthplace, Philadelphia's Independence National Historical Park. Although Washington is the nation's capital, Philadelphia was the home of Congress and the Supreme Court for 10 years while the District was being built. Explore the remnants of that history at this large national park, where you can view the Liberty Bell, tour Old City Hall, or just enjoy the public green spaces. Everything is free except for the National Constitution Center. You will need tickets for tours of Independence Hall, but they won't cost a thing.