Azufral

Azufral is a dormant stratovolcano in Colombia's Nariño department, sitting close to the Ecuadorian border at high Andean altitude. Its caldera, roughly 2.5 by 3 kilometers across, contains around a dozen lava domes formed during its last eruptive episodes approximately 3,600 years ago, along with active fumarole fields still venting sulfurous gases today. The defining feature is the Laguna Verde, a brilliant emerald-green crater lake on the caldera's northwestern rim whose vivid color results from high sulfur concentrations. The hiking trail to the summit starts near the town of Túquerres and crosses characteristic páramo moorland before reaching the crater rim, where on clear days the views extend across the cordillera to neighboring active volcanoes including Cumbal.