Quoting Wikipedia: "Founded in the 10th century, the Rila Monastery (Рилски манастир) is regarded as one of Bulgaria's most important cultural, historical and architectural monuments and it is a key tourist attraction for both Bulgaria and Southeastern Europe as a whole."
It took us four hours of driving to find the monastery. It seems that the GPS maps of Bulgaria are not as accurate as they could be :-)
The monastery is lost in the mountains, and I wouldn't want to spend a whole winter there!