Russian folk music includes significant contributions from ethnic minorities, who populated the Russian Empire, the Soviet Union and modern-day Russia. Russia today is a multi-ethnic state with over 300 ethnicities living under one flag. Each of these ethnic groups has their own indigenous folk, sacred, and art music. Russian music includes a variety of styles: from folk songs to the sacred music of the Russian Orthodox Church. It also includes the legacy of several prominent 19th century classical and romantic composers. Major contributions by 20th century Soviet composers as well as various forms of popular music are also part of the make-up of Russian music. Russia has a history of classical music innovation. Russians take great pride in their cultural music heritage, and in the Soviet Union era nearly everyone, factory worker and farmer included, made regular visits to the theater, concert halls, or opera houses. One of the most recognizable and well-known instruments in Russian music is a plucked string instrument with a triangular body, the Balalaika. Other instruments include the button and keyboard Accordions, a pan flute called the Kalyuki, the Mandolin and the Psaltery.