Flores crater lake

This is one of a set of three volcanic crater lakes in central Flores, and island in eastern Indonesia. The three lakes are part of the same volcano, Kelimutu,and have 3 different colors. At the time of taking this photo, in 2002, they were aqua, black (although it was meant to be blue, see below)and red. Over time, the lakes change or even exchange color, sometimes unexpectedly.

Wikipedia says: Kelimutu is a volcano, close to the town of Moni in central Flores Island of Indonesia containing three summit crater lakes of varying colors. Tiwu Ata Mbupu (Lake of Old People) is usually blue and is the westernmost of the three lakes. The other two lakes, Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Maidens) and Tiwu Ata Polo (Bewitched or Enchanted Lake) are separated by a shared crater wall and are typically green or red in color, respectively. The lake colors do vary on a periodic basis.