Kawah Putih lake, Hank888
"The Kawah Putih site was opened to visitors in 1987. The lake is 2,430 meters, 7970 feet, above sea level so the local climate is often quite chilly (temperatures are frequently around 10 degrees celsius). This makes a brisk change from the humidity of the north Java plain and the capital city of Jakarta. Kawah Putih is a sizeable highly acid lake (pH 0.5-1.3) which changes colour from bluish to whitish green, or brown, depending on the concentration of sulfur and the temperature or the oxidation state. The sand and rocks surrounding the lake have been also leached into whitish colours through interaction with the acidic lake waters (with possible mineral precipitation as well)."