The 400-acre (160-hectare) site on which the Mesa Laboratory of the National Center for Atmospheric Research stands, is maintained as a nature preserve. Behind the laboratory is the Walter Orr Roberts Weather Trail, dedicated in 1997, the nation's first interpretive trail that focuses on weather and climate. Eleven signs along the 0.5-mile (0.8-kilometer) trail explain phenomena visible at various times of the year from the mesa-top site of the National Center for Atmospheric Research. The wheelchair-accessible trail is open all year.