Siam, officially the Kingdom of Siam (Siamese: ราชอาณาจักรสยาม), is a nation located in Southeast Asia, at the center of the Indochina peninsula. It shares borders with India to the west, Malaya to the west-southwest, China to the north, and Vietnam to the east. Siam has been in contact with the western world for centuries, but is even older, with the first of four Siamese kingdoms having been established in 1238 AD. Located in a turbulent area of the world, Siam has been faced by war on its borders for the past century, having gone to war against France in World War I as a member of the Allied Powers, and against Imperial Japan in World War II, during which it underwent a brutal Japanese occupation from 1941-45. Along with neighboring India and later Vietnam, Siam served as a regional bulwark against the spread of Communism in the Cold War, and as a key US ally, sent troops to fight in the closing decade of the Sumatra War. Notably, Siam and the People's Republic of China have nearly gone to war twice in the past forty years, which has resulted in their common border becoming one of the most heavily fortified in the world.