Fort San Lorenzo was built by the Spaniards at the mouth of the Rio Chagres  on Panama's Caribbean coast sometime in the late 1500's.   It was an extremely strategic position, guarding the mouth of the Rio Chagres river which was the entrance to the route across the isthmus to the Pacific Ocean from whence came the treasures destined for Spain.  Henry Morgan captured the fort in 1670 which enabled him to cross the isthmus and sack Panama City.  Canons still point out across the river. The moat and dungeons still stand and it is possible to picture a little of what life must have been like for the garrison there.