June 18, 2009 11:48 am Hidden City Philadelphia You may think you’ve seen all Philadelphia has to offer. But, its richest treasures are unknown to most. You can explore the hidden city of Philadelphia and unlock the past, which has since been lost. US & World Videos 0:16 Philadelphia police department combines 2 police districts. This is why 0:16 Philly's Rocky statue getting a spring cleaning 1:47 New nationwide Xfinity ad features 3 Vietnam War vets as Military Appreciation Month begins 1:08 Philly police believe teenage girl stabbed grandmother to death inside rowhome 2:10 ‘You're speechless and can't believe what you saw.' Mom sees video of attack on her autistic son on SEPTA train