Schoolhouse Rock! is an American interstitial programming series of animated musical educational short films (and later, videos) that aired on YTV in Canada and on Nickelodeon in the U.S. The topics covered included grammar, science, economics, history, mathematics, and civics. The series' original run lasted from 1973 to 1985; it was later revived with both old and new episodes airing from 1993 to 1999. Additional episodes were produced in 2002 and 2009 for direct-to-video release.