Bulgarian culture is rooted in the ancient Thracian civilization, with many impressive monuments from that era still standing today. Some of Bulgaria's most significant cultural sites are recognized by UNESCO as being of international importance, including the medieval Boyana Church near Sofia and the old town of Nessebar on the Black Sea coast. Traditional Bulgarian folk arts reflect the customs and natural beauty of the country. Bulgarian folk music and the Mystery of Bulgarian Women's Voices choir have achieved international success. Major holidays like Easter and Christmas retain old customs centered around foods, songs, and decorations.