At the turn of the 20th century, J. Stuart Blackton produced a series of stop-motion blackboard films. His most successful of these was the "Humorous Phases of Funny Faces," released in 1906.
Winsor McCay produced what many consider the first modern animated film, "Gertie the Dinosaur," in 1914. This was the first time that a fully-designed character appeared in the film. He also developed the concept of keyframe, which controls perspective and speed rates of what the viewer sees.
Cel animation was developed by John Randolph Bray and Earl Hurd. This created the concept of an animator drawing characters moving over a series of frames. The animator would draw the characters on a cel and place them over a background that only needed to be drawn once.
Walt Disney is the creator who changed the direction of animation and made it a highly profitable industry. In addition to his cast of characters led by Mickey Mouse, he produced the first feature-length animated film, "Snow White," in 1937.
Computer animation has revolutionized the industry since its inception in the early 1970s. The first film to use the technique was "Westworld" in 1973. The technology was further developed by the company Pixar, which eventually released the first fully computer animated film, "Toy Story," in 1995.