Mauna Kea, Hawaii, United States

Mauna Kea, Hawaii, rises 4,207 metres above sea level, placing it above 40% of Earth's atmosphere and significantly reducing atmospheric distortion. This altitude enables 13 world-class observatories to operate here, offering views that are sharper than those from Atacama Desert for faint deep-sky objects. The mountain's volcanic peak, however, sits on sacred Hawaiian land, a deeply contentious issue that casts a shadow over its astronomical prominence.