Cabo Rojo Lighthouse (Faro Los Morrillos de Cabo Rojo)

Construction began in 1878 and finished in 1882, the work of the Spanish government on 200-foot limestone cliffs at Puerto Rico's southwestern tip. The lighthouse guides ships through the Mona Passage between the Caribbean Sea and the Atlantic — a job it still performs, now automated. According to locals and scholars, renovations gutted the internal structure, leaving little of historical significance inside. What endures is the position itself: cliffs at the edge of the island, salt flats nearby that have been worked continuously since the time of the Taíno.