Fodor's Expert Review Reserva Natural Las Cabezas de San Juan

The 316-acre reserve on a headland north of Fajardo is owned by the nonprofit Conservation Trust of Puerto Rico. You ride in open-air trolleys and wander down boardwalks through seven ecosystems, including lagoons, mangrove swamps, and dry-forest areas. Green iguanas skitter across paths, and guides identify other endangered species. A half-hour hike down a wooden walkway brings you to the mangrove-lined Laguna Grande, where bioluminescent microorganisms glow at night. The restored Fajardo Lighthouse is the final stop on the tour. Its Spanish colonial tower has been in operation since 1882, making it Puerto Rico's second-oldest lighthouse. The first floor houses ecological displays, and a winding staircase leads to an observation deck. The only way to see the reserve is on a guided tour; reservations are required and can be made through the trust's website.