After the great earthquake of 1906, Union Square became San Francisco's premier shopping district, and, by the 1930s, the site of the world's first underground parking structure. 420 Mason Street was originally built in the 1890s as a Victorian Playhouse by celebrated architect August Headman. In the 1940s it became a USO club called the "Stage Door."
Later it started showing films as the "Stage Door Theatre" and hosted the premiere of the Alfred Hitchcock film Vertigo on May 9, 1958.
By the early 1980s, it had become the Regency III movie theater (the Regency I and II were located several blocks away) before becoming Ruby Skye.