Mount Rinjani is Indonesia’s second-highest volcano and the site of the Segara Anak caldera lake.
The volcano rises to 3,726 metres on Lombok, an island east of Bali. Rinjani’s immense summit caldera contains Segara Anak, a striking blue lake whose name means “Child of the Sea.” A smaller active cone, Mount Barujari, rises within the caldera and has erupted repeatedly in modern times.
A catastrophic eruption around 1257 produced one of the largest known volcanic events of the last millennium. Scientists associate that eruption with major climate effects recorded in tree rings and historical evidence around the world. The event also helped create the modern caldera landscape.
Mount Rinjani is protected within Mount Rinjani National Park, established in 1997. Trekking routes pass through forest, savanna and steep volcanic terrain. Authorities sometimes close the mountain because of eruptions, earthquakes, heavy rain or dangerous conditions around the crater.