Nine historical and natural objects are UNESCO World Heritage Sites:  Pirin National Park, Sreburna Nature Reserve, the Madara Rider, the Thracian tombs in Sveshtari and Kazanlak, the Rila Monastery, the Boyana Church, the Rock-hewn Churches of Ivanovo and the ancient city of Nesebar. The Rila Monastery was established by Saint John of Rila, Bulgaria's patron saint, whose life has been the subject of numerous literary accounts since Medieval times.