The most important service activity in Cambodia is associated with tourism, which is one of the major sources of overseas investment and the fastest-growing segment of the economy. Tourism has become an important source of revenue and foreign exchange and has helped mitigate the effects of large trade deficits. Much of this investment goes into constructing hotels, developing resorts, and enhancing facilities serving tourists visiting Angkor Wat and Phnom Penh. The number of tourists has been increasing and diversifying. While the first visitors were primarily from socialist countries, Japan, and other parts of Asia, many tourists now arrive from France, the United Kingdom, the United States, and other areas predominantly in Europe and North America.