Spain built these lighthouses at the edge of empire — and the edges were exactly where the danger was. Construction on the Cabo Rojo lighthouse began in 1878 and finished in 1882, a Spanish project on 200-foot limestone cliffs at the island's southwestern tip, set to guide ships through the Mona Passage between the Caribbean Sea and the Atlantic. At Vieques, the lighthouse at Punta Mulas went up between 1895 and 1896, its lantern room 68 feet above sea level, its light reaching eight miles out — exactly the distance to mainland Puerto Rico. At Rincón, Spain finished a third in 1892; the 1918 earthquake took it down, and the U.S. Coast Guard put up a plainer replacement in 1922. Three lighthouses, three sovereignties, the same job: mark the passage, hold the position. The cliffs at Cabo Rojo are still working.
