The Boiling Lake is a flooded fumarole about 60 metres across in the volcanic rainforest of Dominica, in the Caribbean, the second-largest hot lake in the world, its edges at 90 degrees and its grey centre in a permanent rolling boil under a cloud of steam, and it is reached by a hard walk of three to four hours each way from the village of Laudat, hours from any road. The lake is a vent of the Morne Trois Pitons volcano, where gases and steam rise through a crack in the crater floor and heat the water that collects in the hollow, and the trail to it is the reason the island is called the nature island: it climbs at once out of Laudat into elfin woodland, dwarfed trees draped in moss, cool and dripping even in the dry season, over the ridge of Morne Nicholls, and then drops into the Valley of Desolation, a barren, steaming basin stripped of plants by acid and heat, its ground stained yellow and orange with sulphur, with hot streams and bubbling mud pots beside the path. Beyond the valley the trail crosses a warm river and scrambles up the last ridge to the rim.
The ridge is as far as the path runs. From it the lake lies directly below, boiling in the middle and steaming to its edges, and on a still day the cloud lifts long enough to see the whole grey surface heave; the walk back is the same way, with a swim in the warm pools of the Titou gorge at the end, a slot canyon below the trailhead. Every few decades the lake simply empties, draining through its vent and leaving a steaming pit, as it did in 2004, and fills again months later. The walk is done with a local guide, and the weather on the ridges changes in minutes. The Boiling Lake is a pot of water that the island keeps on the fire, and the walk to it is Dominica in a day.