A number of ancient civilizations, including the Thracians, Ancient Greeks, Romans, Ostrogoths, Slavs, Varangians and probably Bulgars, have left their mark on the culture, history and heritage of Bulgaria. Because of this Bulgarian nation has one of the richest folk heritage in the world. Thracian artifacts include numerous tombs and golden treasures, while ancient Bulgars have left traces of their heritage in music and early architecture. Thracian rituals such as the Zarezan, Kukeri and Martenitza are to this day kept alive in the modern Bulgarian culture.
The oldest treasure of worked gold in the world, dating back to the 5th millennium BC, comes from the site of the Varna Necropolis.
Bulgaria functioned as the hub of Slavic Europe during much of the Middle Ages, exerting considerable literary and cultural influence over the Eastern Orthodox Slavic world by means of the Preslav and Ohrid Literary Schools. Bulgaria also gave the world the Cyrillic script, the second most widely used alphabet in the world, which originated in these two schools in the tenth century AD.
Bulgaria's contribution to humanity continued throughout the nineteenth and twentieth centuries, with individuals such as John Atanasoff — a United States citizen of Bulgarian and British descent, regarded as the co-father of the digital computer. A number of noted opera-singers (Nicolai Ghiaurov, Boris Christoff, Raina Kabaivanska, Ghena Dimitrova, Anna Tomowa-Sintow, Vesselina Kasarova), pianist Alexis Weissenberg, and successful artists (Christo, Pascin, Vladimir Dimitrov) popularized the culture of Bulgaria abroad.