West Side Story is a musical with music by Leonard Bernstein, lyrics by Stephen Sondheim, and book by Arthur Laurents. It opened on Broadway in 1957 and had two major revivals, in 1980 and 2009. The plot is based on Romeo and Juliet but transposed to mid-20th century New York City and revolving around rival gangs, the Jets and Sharks. It features famous musical numbers like "Somewhere", "Jet Song", "Tonight", and "America". The 2009 revival incorporated some Spanish dialogue into the English lyrics.