Declared a Unesco World Heritage Site in 1980, Fuerte San Lorenzo is perched at the mouth of the Río Chagres on a promontory west of the canal. Despite its violent history, much of San Lorenzo is well preserved, including the moat, cannons and vaulted chambers. The fort also commands a wide view of the river and bay far below, which was one of the reasons the Spanish chose to build here.
San Lorenzo was constructed of blocks of cut coral and armed with row upon row of cannons. If you inspect the cannons closely, you’ll notice that some of them are actually British-made, dating from the time in the 17th century when Sir Francis Drake and his privateer brethren occupied the fort.