Images of the cosmos from the Hubble Space Telescope and the James Webb Space Telescope have awed the public and astronomers alike. Until the Hubble, breakthroughs in astronomy came from big telescopes on mountain-top observatories—discoveries that include the expansion of the Universe and planets orbiting other stars. A new generation of extremely large ground-based telescopes is under development, which, when paired with space-based observatories, will produce even more remarkable discoveries about our Universe.