Hike the trails of El Yunque National Forest to experience the only rain forest in the U.S. National Park system. El Yunque is a tropical rainforest in northeastern Puerto Rico. From El Portal Visitor Center, a walkway winds through the surrounding treetops. Trails run to La Mina waterfall and Mount Britton, then up to the high-altitude dwarf forest. In the south are ancient petroglyphs, made by the area’s indigenous Taíno people. The forest comes alive with the nightly calls of coquí tree frogs. Hours are 7:30am-6:00pm daily.