Joseph Plateau developed the phenakistiscope in 1832, which led to the development of animation over several decades. Key early animated films included Windsor McCay's 'Gertie the Dinosaur' in 1914, Disney's 'Steamboat Willie' featuring Mickey Mouse in 1928, and Fleischer Studios created 'Betty Boop' and 'Popeye' in the 1930s. 'Toy Story' released in 1995 was a breakthrough as the first full-length 3D computer-generated animated feature film.