The walk to Emerald Pool is a short trail through some of the most lush forest on the island. Tree ferns taller than a house line the path, and the air is cool and damp with the sound of birds all around. The trail includes a wooden viewing platform where you can look out over the rainforest canopy to the Atlantic Ocean in the distance.
The pool itself sits in a bowl of dark volcanic rock. The waterfall that feeds it drops about six metres — about the height of two tall adults standing on each other's shoulders. Swimmers can stand under the waterfall for a natural shower, and the water is refreshingly cool even on the hottest day.
Emerald Pool gets its vivid green colour from tiny plants — mosses and algae — that grow on the rocks under the water and around the edges. When sunlight filters through the forest leaves above and hits the water, it makes the green glow even brighter. Early morning is the best time to visit, when the light comes through the canopy in long golden beams.