Visitors to Independence National Historical Park view the Liberty Bell Friday, April 8, 2011, in Philadelphia as negotiations continue in Washington to avoid a government shutdown, which would close national parks and many other federal services. (AP Photo/Matt Rourke)

Photo by: Matt Rourke

Visitors to Independence National Historical Park view the Liberty Bell Friday, April 8, 2011, in Philadelphia as negotiations continue in Washington to avoid a government shutdown, which would close national parks and many other federal services. (AP Photo/Matt Rourke)