The caldera resulted from the eruption and collapse of a 14,000-foot peak over 1 million years ago; the flow out the bottom created the Pajarito Plateau and the ash from the eruption spread as far east as Kansas. You can't imagine the volcanic crater's immensity until you spot what look like specks of dust on the lush meadow floor and realize they're elk. The Valles Caldera Trust manages this 89,000-acre multiuse preserve with the aim to "protect and preserve the scientific, scenic, geologic, watershed, fish, wildlife, historic, cultural, and recreational values of the Preserve, and to provide for multiple use and sustained yield of renewable resources within the Preserve."
The preserve is open to visitors for hiking, cross-country skiing, horseback riding, horse-drawn carriage rides, van wildlife photography tours, mountain-bike tours, bird-watching, fly-fishing, and may other outdoorsy endeavors. Some of the activities require reservations and a fee, although there are four free,
relatively short hikes, two of them signposted from the parking area along NM 4, and two others near the information center by the check-in station. About 20 miles southwest of the preserve entrance, the Valles Caldera Visitor Center at 18161 NM 4 is another good place to learn about park activities.