Hafa adai! In this site you can learn all about World War II on the U.S.'s territory, Guam! Guam is a small island in the Marianas that is right above the Mariana Trench. The natives of Guam are called the Chamorros. The Chamorro people came from Asia somewhere around 2000 B.C. During World War II, the Japanese changed Guam and its native people.