El Yunque National Forest 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 Ta no people. The forest comes alive with the nightly calls of coqu tree frogs. In 2010 the United States Mint began issuing 56 quarter-dollar coins featuring designs depicting national parks and other national sites as part of the United States Mint America the Beautiful Quarters Program.