Thru' The Trees, Washington, D.C. (1923)
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. Or