Mysterious sarcophagus found below fire-damaged Notre Dame cathedral will soon be opened and its secrets revealed

A mysterious leaden sarcophagus discovered in the bowels of Paris' Notre Dame cathedral after it was devastated by a fire will soon be opened and its secrets revealed, French archaeologists said Thursday.

The announcement came just a day before the third anniversary of the inferno that engulfed the 12th century Gothic landmark, which shocked the world and led to a massive reconstruction project.

During preparatory work to rebuild the church's ancient spire last month, workers found the well-preserved sarcophagus buried 65 feet underground, lying among the brick pipes of a 19th century heating system.