Founded in 1935 as the Film Library, this department's collection now includes more than 22,000 films and four million film stills; the strongest international film collection in the United States, it incorporates all periods and genres. Among the holdings are original negatives of the Biograph and Edison companies, and the world's largest collection of D. W. Griffith films. The film collection is stored in the Museum's Celeste Bartos Film Preservation Center, a state-of-the-art facility that opened in June 1996. The Department's video collection, begun in 1970, includes some 1,000 works dating from the 1960s to the present, ranging from educational pieces and broadcast documentaries to works by video artists.