Places to visit in Pennsylvania

Hi,

For the ones living in Pennsylvania, what would you suggest to discover the region?

When you have friends or family visiting you, where do you go with them? What are the must-see places in Pennsylvania, the tourist sites?

How to visit the region in an original way? Any unusual or unknown place to recommend?

What would you suggest for a couple of days of for a week of holidays in Pennsylvania?

Thank you in advance for participating ;)

Julie

Come to the Lehigh valley, plenty of free music from May to September.  Check out fest.org and Steelstax Levitt Pavilion