Mt Athos (2 030m), where some 20 monasteries cling to the slopes, is the site of Orthodox monasticism at its purest. These timeless strongholds of Byzantine art make up a unique site - a UNESCO World Heritage Site -, the treasures and atmosphere of which leave some of the most lasting memories of a trip to Greece. At least, that is, for the handful of visitors who are allowed inside: it is only open to "diamonitirion" (permit) holders and remains closed to women.