Lithuanian National Opera and Ballet Theatre (LNOBT) is an opera house and ballet theatre in Vilnius, Lithuania. It was built in 1974. 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.