How freaky is this!?!?!?! And how long have they been there? Could they be some of the world's most famous historians!?
Here are the details from our friends at Philly.com:
A team of volunteer archaeologists and anthropologists are racing against the clock to excavate what may prove to be as many as 300 historic gravesites discovered during a residential construction project on Arch Street in Old City in the last two weeks.