Congress Hall at 5th and Chestnut is the less celebrated part of Independence Square, but just as historic as Independence Hall. From 1790 to 1800 it served as home of the US Congress while Philadelphia was the temporary US capital.
Unlike Independence Hall, there are no timed tickets, making it easier to visit. There is still a security screening, which rivals those at airports.
A park ranger leads the tour. The first floor is where Congress met.
Upstairs was where the Senate met, a literal upper and lower chambers. As always, Senators got the nicer digs.
That Philly Life: Urban Exploring in Philadelphia 