About 1,600,000 people.

Philadelphia is the biggest city in Pennsylvania and one of the most important cities in American history. It is where the Declaration of Independence and the Constitution were signed, so people call it the birthplace of the United States.
You can see the famous Liberty Bell with its big crack, run up the Rocky Steps at the art museum, and eat a real Philly cheesesteak sandwich. The Please Touch Museum and the Franklin Institute are super fun for kids.
Independence Hall and the Liberty Bell sit right downtown, where you can walk the same streets as the founders of the country.
Fairmount Park is one of the largest city parks in the country, with trails, rivers, and old mansions to explore.