More than 240 inches of rain—100 billion gallons!—falls annually in the forest, making it a rich habitat for moisture-loving flora and fauna. It is home to more than 1,000 plant species, including 50 types of orchids, 150 ferns, and 240 species of trees, 23 of which are endemic only to El Yunque.

The Caribbean National Forest is in the Sierra de Luquillo, with mountains ranging in height from 600 feet to more than 3,500 feet above sea level, and it contains four distinct forests. Most of the area is covered in the Tabonuco Forest, found in areas up to 2,000 feet above sea level. This is the most dramatic part of the forest and site of the true rain forest. The dominant tree species is the tabonuco, which grows up to 125 feet in height and is distinguished by its huge dark-green canopy and straight trunk, which has a smooth whitish bark.

The Sierra Palm Forest is found along steep slopes and near rivers and creeks more than 1,500 feet above sea level. Its dominant tree, the sierra palm, is easily identified by the thick skirt of exposed roots around its base, which is an adaptation that allows it to thrive in the wet soil. The Palo Colorado Forest is found in valleys and slopes at an altitude between 2,000 feet and 3,000 feet. The dominant tree is the palo colorado, also known as swamp cyrilla, which is characterized by its thick twisted trunk and red bark. Most of these trees have been around for ages—some reportedly more than 1,000 years.

On the uppermost peaks of El Yunque, between 2,500 and 3,500 feet above sea level, is the Cloud Forest, also known as the Dwarf or Elfin Forest. This is a nearly mystical, otherworldly place where constant wind and moisture have stunted and twisted the dense vegetation. Roots snake across the windswept ground in thick tangles, and the trees, which don’t exceed 12 feet in height, are covered with moss and algae. Here you also find many species of ferns and bromeliads, which bloom with brilliant red flowers. The air is cool, and visibility is often obscured by misty cloud covering.