Of course, the boys are long gone.  But it's amazing to think about all the voids that are underneath this city.  Someone said
it's as though they built a city on toothpicks.  These mines extended all under the city.  Notice what appears to be gas lamps on the boys' helmets.  When they excavated the site for the Royal Theater, they exposed one of these mine voids.  Mining activity in Northeastern Pennsylvania dramatically decreased after January 22, 1959.  On this date, the Pennsylvania Coal Company illegally mined too close to the Susquehanna River, causing the river to break through the mine's roof.  This breakthrough, of course, flooded this particular mine.  But apparently, many of the mines connected underground.  So, this flood reportedly wiped out a large portion of the then-existing mines.  This disaster is generally referred to as the Knox Mine Disaster, being named after the mine which caused the flood.  Twelve miners lost their lives in the disaster.  The photos of this breakthrough and resulting flood are pretty dramatic.  The breakthrough caused a huge whirlpool in the middle of the Susquehanna River.  In an attempt to plug this hole, they quickly ran a rail line to the site and pushed empty railroad cars into the void.  In the end, these attempts were futile.  [Click here to read more about the disaster]