The term "Centennial State" is used to refer to Colorado due to it becoming a state in the United States of America in 1876, the same year as the 100th anniversary of the Declaration of Independence. Other synonyms for Colorado include the "Rocky Mountain State" due to its location in the Rocky Mountains, "Colorful Colorado" due to its diverse landscapes, "The Highest State" due to having the highest elevation in the US, "The Mile High State" due to Denver's elevation, and "The Mother of Rivers" due to it being the origin of several major rivers. Each of these titles celebrates different aspects of Colorado's unique geography and history.