Okinawa in located in southwestern Japan. It consists of hundreds of islands, most of them belong to subtropical climate. Temperatures are above 20 degree Celsius for most of the year. Okinawa had been a nation called “Ryukyu Kingdom,” with close ties to China, until the 19th century. Various buildings in Okinawa convey its unique history. Okinawa became a battlefield during the World War II. After the war, Okinawa was under U.S. control. Though Okinawa was returned to Japan in 1972, more than 70% of U.S. forces in Japan is stationed in Okinawa.