Mount Athos is a mountain and a peninsula in Macedonia, northern Greece and a UNESCO World Heritage Site.
A UNESCO World Heritage Site, this peninsula of 390 km² houses some 1,400 monks in 20 Eastern Orthodox monasteries. An autonomous state under Greek sovereignty, entry into the area is strictly controlled and only male residents are allowed to live there and only male visitors are allowed.
Mount Athos is where monks go to escape the modern world, and as you're visiting as a guest, you have to respect their rules and behave as they expect you to. In general terms, monks expect pilgrims to visit them, and not tourists.