Cabo Rojo Lighthouse (Faro Los Morrillos de Cabo Rojo)

The Spanish built this lighthouse on limestone cliffs above the Caribbean Sea to guide ships through the Mona Passage — and it still does. Construction began in 1878 and finished in 1882; the lighthouse shares its layout with others the Spanish built across Puerto Rico during the same period. It's been renovated and automated since, though locals note the renovations gutted much of what made the interior historically significant. The cliffs alone are reason enough to make the walk.