Trans-Siberian Orchestra (TSO) is an American progressive rock band founded in 1993 by producer, composer, and lyricist Paul O'Neill, who brought together Jon Oliva and Al Pitrelli (both members of Savatage) and keyboardist and co-producer Robert Kinkel to form the core of the creative team. Since then, TSO has sold more than 9 million concert tickets and over 8 million albums. The band's musical style incorporates classical, orchestral, symphonic, and progressive elements into hard rock and heavy metal. The band has released a series of rock operas: Christmas Eve and Other Stories, The Christmas Attic, Beethoven's Last Night, The Lost Christmas Eve (the final installment of their Christmas trilogy), and their two-disc Night Castle. Trans-Siberian Orchestra is also known for their extensive charity work and elaborate concerts, which include a string section, a light show, lasers, pyrotechnics, moving trusses, video screens, and effects synchronized to music.