Kelimutu is a volcano, close to the small town of Moni in central Flores island in Indonesia. The volcano is around 50 km to the east of Ende, Indonesia, the capital of Ende regency in East Nusa Tenggara province. The mountain has three volcanic crater lakes that differ in color.
The science of the Kelimutu lakes is relatively well-known. Lake colors periodically change due to adjustments in the oxidation-reduction status of the fluid of each lake, and also considering the abundance of different major elements, such as iron and manganese. Oxidation-reduction status depends on the balance of volcanic gas input and rainfall rate, and is thought to be mediated by the groundwater system in the volcano itself.
Wikipedia https://en.wikipedia.org/wiki/Kelimutu
Address 86318, Indonesia
Coordinates -8°45'51.527" N 121°48'44.376" E