PHILADELPHIA — U.S. Park Rangers are investigating a fire that broke out within the Independence National Historical Park in Old City last week. An officer discovered the blaze at 8 p.m. on Dec. 24 in the basement of a building in the 300 block of Chestnut Street, the park’s public affairs office said in a statement. The incident is being investigated as arson. Reports say the blaze was lit in Carpenter’s Hall. The historic building was home to the First Continental Congress in 1774 and is considered the birthplace of the Commonwealth of Pennsylvania. The fire engulfed the basement before firs...