The Monastery of Saint Ivan of Rila is the largest and most famous Eastern Orthodox monastery in Bulgaria. Founded in the 10th century, the Rila Monastery is regarded as one of Bulgaria´s most important cultural, historical and architectural monuments and is a key tourist attraction for both Bulgaria and Southeastern Europe. The monastery complex, regarded as one of the foremost masterpieces of Bulgarian National Revival architecture, was declared a national historical monument in 1976 and became a UNESCO World Heritage Site in 1983.