TONLE SAP (north of Phnom Penh) is the largest freshwater lake in Southeast Asia at the end of the wet season but is only a large lake in the dry season when it shrinks to a fraction of its wet season size Stretching almost all the way from Phnom Penh to Angkor Wat, it provides water for half of Cambodia's crops, and yields fish that supplies Cambodia’s population with half its protein It is also one of the country’s most important transportation links.