The Griffith Observatory was designed by John C. Austin and Frederick M. Ashley and opened in 1935 on the southern slope of Mount Hollywood, at an elevation of 350 metres above the Los Angeles basin. It was paid for from a bequest by Griffith J. Griffith, the Welsh-born mining tycoon who deeded the surrounding parkland and observatory funds to the city on the condition that the facility remain free to the public, in perpetuity.
The plan is a Greek cross with three principal volumes capped by copper domes: a central pavilion containing the planetarium, and two flanking wings each terminating in a smaller dome that houses a solar telescope. The composition is rigorously bilaterally symmetric, organised on a single strong central axis that runs through the entrance, the central rotunda, and out to the lawn beyond. The exterior is finished in smooth-troweled cement plaster, painted off-white, with low-relief sculptural ornament concentrated at the entrance frieze, the rotunda drum, and the dome bases. The three copper domes have weathered to a characteristic verdigris green, providing the principal colour accent against the white walls. The detailing is the disciplined linear vocabulary of late Art Deco: hard horizontal cornice bands, stepped parapets, geometric relief, and a frieze of the figures of the great astronomers above the entrance. Below the planetarium dome is a circular hall, the Hall of the Sky, beneath which a Foucault pendulum swings continuously through a polished bronze armature in the floor. Beneath the entire complex is the Samuel Oschin Planetarium and a series of exhibition galleries extended in a 2002–2006 renovation by Pfeiffer Partners.
The Observatory is one of the defining public buildings of Los Angeles, and a key example of the way the city used civic architecture in the 1930s to claim a cultural identity equivalent to its older East Coast counterparts. It has appeared in countless films, from Rebel Without a Cause to La La Land, and is now the most visited public observatory in the world.