Philadelphia's collection of museums is one of the most impressive in all of the United States.  You'll be able to find the more renowned ones, such as the Franklin Institute and the Academy of Natural Sciences, grouped together along the Benjamin Franklin Parkway.  

For more of the Colonial-era buildings, such as Fireman's Hall, Elfreth's Alley, and Betsy Ross House, be sure to take a walking tour of the historic district, which is located near the waterfront on Front through Sixth Streets.