Two of the most important documents in American history (the Declaration of Independence and the Constitution) count Independence Hall as their birthplace. The gorgeous, meticulously preserved space is gorgeous and definitely a must-see. But know this: If you're going in March through December, you'll need tickets (albiet, free) to enter. Pick up or select your tickets at the ranger's desk. You can also get advanced tickets online, but there is a handling fee.
Across the street from Independence Hall you'll find the Liberty Bell, which really is all it's cracked up to be. Although the bell was rung only once, it became a symbol of freedom. The center includes the bell itself as well as in-depth exhibits about the bell's relationship to abolition and women's suffrage.
Visit the place where the first American flag was made and learn the story of its seamstress, Betsy Ross. Take an audio tour and visit with Betsy herself (OK, a historic reenactor playing the part of the leading lady) in the upholstery shop.
If all the historic sightseeing leaves you hungry -- for food and more history lessons -- stop at City Tavern. The restaurant has a storied past and witnessed many of the Revolutionary period's significant events. Today, you can experience an 18th-century meal, served by historical reenactors, in the preserved tavern.
The Continental Army spent the winter of 1777-1778 camped at Valley Forge. At that point, the outlook was uncertain for General George Washington and his army, but as history tells us, the tides would soon turn. Today, explore the encampment, which celebrates the perseverance of the Revolutionary War patriots. The site is tucked into a larger national park, which offers plenty of other adventures, including camping and hiking.
The location of Blairsville made it a hub of railroad, canal, and road travel in the 19th century. Because of its transportation capabilities, it also became an integral stop on the Underground Railroad. Today, the BlairsvilleUnderground Railroad Museum honors the efforts of the Underground Railroad operators. Tours are available by appointment only, but the museum hosts events from time to time. Find the details on their events calendar.
Plan to spend a whole day at Gettysburg. Start at the visitor's center and settle in to watch "A New Birth of Freedom" and view the Cyclorama. Stroll through the museum, which includes interactive exhibits. Then head out for a battlefield tour (the National Park Service recommends blocking off four hours for the tour). You can walk the battlefield on your own, but going with a licensed battlefield guide is definitely a richer experience.
Turning to more recent history, the Flight 93 Memorial commemorates the heroic efforts of the passengers and crew who thwarted an attempt to crash a plane into a target in Washington, D.C. The park includes the Memorial Plaza at the crash site, a visitor's center, and walking trails.
Railroad Museum of Pennsylvania: The railroads played a significant part in the shaping of industrial Pennsylvania and the landscape of the country beyond.
The Johnson House: a significant stop on the Underground Railroad.
Elfreth Alley: America's oldest residential neighborhood. If you love homes, this is a must-see.