Valles Caldera is a 13.7-mile wide volcanic caldera in the Jemez Mountains of northern New Mexico. Hot springs, streams, fumaroles, natural gas seeps and volcanic domes dot the caldera floor landscape.

About 1.25 million years ago, a spectacular volcanic eruption created the 13-mile wide circular depression now known as the Valles Caldera. The preserve is known for its huge mountain meadows, abundant wildlife, and meandering streams. The area also preserves the homeland of ancestral native peoples and embraces a rich ranching history.

Valles Caldera is home to the second largest elk population in New Mexico. Other popular residents include Gunnison prairie dogs, coyotes, badgers, black bears, Eastern mountain bluebirds, and golden eagles.

Los Alamos is a town in Los Alamos County, New Mexico, United States, that is recognized as the development and creation place of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Laboratory during World War II.