Bulgaria is one of the world's oldest grape growing regions, dating back to 4000 B.C. under the Thracian Empire. During the latter part of the 20th century, the industry was state run until the fall of Communism. Today's Bulgaria has five main wine regions – Danube River Plains, Thracian Valley, Black Sea Coast, Rose Valley, and Struma Valley. Primary varieties include Mavrud, Rubin, Shiroka Melnik, Gamza, and Dimiat – as well as international varieties.