"I seen the manhole fly, I don't know, 100, 150 feet in the air. People who were standing around the subway entrance started running this way," said witness Gabe Alvarez.
"It was the biggest boom I ever felt in my life," said witness Donald Ford.
The incident happened just before 2:00 a.m. along Second and Market streets where there is a string of bars and restaurants. Even on a Sunday night it was a bustling scene.
Residents say after the explosions, they saw thick black smoke pouring from the manholes.
Police and PECO crews were on the scene in minutes. They traced the source to a faulty underground power service connection.
The line running to the Continental Restaurant had apparently been damaged, causing the wires to become exposed.
Over time, they overheated to the point where the insulation started smoldering, igniting sewer gas.
PECO says that conduit was inspected this past April, but there's no way of detecting small defects in wire insulation that can cause big problems later.
The explosion also disabled the traffic signals at 2nd and Market, but that was fixed by mid morning.
Second Street was closed to traffic for most of the morning, but has since reopened and things are returning to normal as the repair work continues.
Authorities are just thankful it happened at closing time instead of at the height of the dinner hour.