Lake Maughan occupies the steep-sided walls of the 2.9-km-wide summit caldera of Parker volcano, also known locally as Falen. This low, vegetated stratovolcano overlooks Sarangani Bay near the southern tip of Mindanao Island and is surrounded by extensive, youthful pyroclastic-flow deposits. This volcano was unknown to most volcanologists until recent years, but it is now known to have been the source of a major explosive eruption in 1641. Photo courtesy of PHIVOLCS.