Lithuanian National Opera and Ballet Theatre (LNOBT) (Lithuanian: Lietuvos nacionalinis operos ir baleto teatras) is an opera house and ballet theatre in Vilnius, Lithuania. It was built in 1974. The Lithuanian State Symphony Orchestra, the Kaunas State Choir, and the Lithuanian Chamber Orchestra are housed in the LNOBT. Apart from standard Western and Russian repertory works, the opera also performs national operas. Vytautas Klova's opera Pilėnai (1956), has since 2001 been performed outdoors during the summer at Trakai Island Castle. Bronius Kutavičius' opera Lokys (2000), after Prosper Mérimée's short story Lokis the bear, was commissioned by the Vilnius Festival.