Beautiful blue sky seen from the air plane
Kawah Putih (English: White Crater) is a striking crater lake and tourist spot in a volcanic crater about 50 km south of Bandung in West Java in Indonesia.  Kawah Putih lake (7.10Â° S 107.24Â° E) is one of the two craters which make up Mount Patuha, an andesitic stratovolcano (a "composite" volcano).  Mt Patuha is one of numerous volcanoes in Java. Kawah Putih crater lake itself represents a relatively stable volcanic system with no records of significant activity since around 1600.  The Kawah Putih site was opened to visitors in 1987. The lake is 2,430 meters 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).
Almost the end of the day at santolo island, very calm weather at beauty island