Known as the Friendly Frontier of Texas, Abilene retains its traditional Wild West spirit in a contemporary setting. One fine example of this is Frontier Texas, a museum that brings the Wild West back to life through hands-on displays and modern exhibits that take visitors back to the days when Texas was a lawless expanse of sagebrush. The Abilene Zoo is another popular attraction, boasting over 200 species of animals from around the world and offering admission for a nominal cost. One of the city's more unique attractions is the National Center for Children's Illustrated Literature, a museum that celebrates the book illustrations that stoke young imaginations. The Dyess Air Force Base is found in Abilene as well and is home to bombers and transport planes used by the U.S. military. Located just outside Abilene, the Buffalo Gap Historic Village interprets local history from the 1870s to the 1920s, showcasing American Indian artifacts, Frontier firearms and 20 historic buildings.