Because of the remarkable clarity, dryness, and stillness of the air, and its elevation (with atmospheric pressure of ), as well as the absence of the lights of major cities, the summit of Haleakalā is one of the most sought-after locations in the world for ground-based telescopes (though to a lesser extent than Mauna Kea on neighboring Hawaii). As a result of the geographic importance of this observational platform, experts come from all over the world to take part in research at Science City, an astrophysical complex operated by the U.S. Department of Defense, University of Hawaii, Smithsonian Institution, Air Force, Federal Aviation Administration, and others.