Independence Hall and the Liberty Bell are now protected in a secure zone with entry at security screening buildings . Following the September 11 , 2001 attacks , as part of a national effort to safeguard historical monuments by the United States Department of Homeland Security , pedestrian traffic around Independence Square and part of Independence Mall was restricted by temporary bicycle barriers and park rangers . In 2006 , the National Park Service proposed installing a seven-foot security fence around Independence Hall and bisecting Independence Square , a plan that met with opposition from Philadelphia city officials , Pennsylvania Governor Ed Rendell , and Senator Arlen Specter . As of January 2007 , the National Park Service plan was revised to eliminate the fence in favor of movable bollards and chains , and also to remove at least some of the temporary barriers to pedestrians and visitors
September 11 , 2001 attacks
September 11 attacks
Independence Hall