Hilo, Hawaii

The Mauna Kea Observatories have been controversial since the first telescope was built in the late 1960s. Originally part of research begun by Gerard Kuiper of the University of Arizona, the site has expanded into the world's largest observatory for infrared and submillimeter telescopes. Opposition to the telescope from residents in the city of Hilo, Hawaii were concerned about the visual appearance of the mountain and Native Hawaiians voiced concerns over the site being sacred to the Hawaiian religion as the home of several deities. Environmental groups and activists have been expressing concern over endangered species habitat.

The Outrigger Telescopes Project, intended to build from four to six comparatively small telescopes for interferometry, was to surround the Keck telescopes. It was cancelled in 2006, after a court found NASA's Environmental Impact Statement was improperly limited to just the telescope area.