El Yunque is a rainforest in the mountains of eastern Puerto Rico, the only tropical rainforest in the United States' national forest system, where up to six metres of rain fall a year and the walks lead to waterfalls under a chorus of tiny frogs. The forest climbs from tall trees and giant ferns in the valleys to a dwarf forest on the ridgetops, where gnarled, moss-wrapped trees stand in drifting cloud and the air turns cool and wet, and the peaks are in cloud most of the time. The Taíno called the high peak Yuke, and Spanish settlers heard it as yunque, their word for anvil, which the flat top roughly resembles. Route 191 winds up into the forest through walls of bamboo and dripping green to the stone Yokahú tower, a lookout built in 1963 with the forest below and the Atlantic beyond, and to the trailheads; the paved La Mina trail follows the river down to La Mina Falls, where cold water pours over dark rock into a pool ringed with giant ferns and people swim under the drop.
After dark the forest sings. The coquí, a frog the size of a thumbnail found only in Puerto Rico, calls its own name in two notes, ko-kee, from every leaf, and thousands of them turn the whole forest into a chorus that seems to come from everywhere at once and is the sound of the island. The forest is also the last home of the iguaca, the Puerto Rican parrot, one of the rarest birds on Earth; its wild population crashed to thirteen birds in 1975, all of them here, and captive breeding has brought it back to a few hundred. Hurricane Maria stripped the forest bare in 2017, and it has regrown as it always has. The higher trails climb to the dwarf forest and the peak of El Yunque itself, in cloud, an hour or two above the road. El Yunque is a rainforest an hour from San Juan, and the frogs in it sing the island's name.