Cabo Rojo Lighthouse (Faro Los Morrillos de Cabo Rojo)

Construction began in 1878 and the light first shone in 1882 — the Spanish-built tower at the southwestern tip of Puerto Rico still guides ships through the Mona Passage today. Automated and electrified in 1967, it has since been renovated, though those renovations drew criticism that the work stripped the interior of its historical significance. Salt has been mined in the flats below since before the Spanish arrived. The lighthouse is open to the public and free to enter.