The Mojave Desert is a rain shadow desert located primarily in southeastern California and southern Nevada. It is the smallest of the four North American deserts but contains the lowest and hottest point in North America: Death Valley. The desert is defined geographically by the presence of the Joshua tree, a unique species of yucca that grows nowhere else in the world. The landscape is a mix of mountain ranges, basins, and salt flats. Historically, the Mojave was a major obstacle for pioneers heading to California, and today it remains a center for aerospace and military testing, as well as solar power generation. The desert's climate is characterized by extreme temperature fluctuations, with scorching summers and occasionally snowy winters in higher elevations. Despite the harshness, it supports a diverse array of life, including desert tortoises, Gila monsters, and bighorn sheep.