Thru' The Trees, Washington, D.C.
The earliest extant 3-D demonstration film, dated 1923. William Van Doren Kelley, inventor of the Prizma color process, premiered 'Future' in anaglyphic 3D, in New York around Christmas 1922. Two 3-D films, Plasticons (1922) and New York City (1922) were shown under the name Movies of the Future. Originally about 14 minutes long, it is considered the second known public screening of a 3D film after The Power of Love (1922). A second film, Thru' The Trees, Washington, D.C., was made by William Crespinel, formerly with Kinemacolor and now the main cameraman with Prizma.
