A kalderimi is a cobblestone-paved road built for hoofed traffic. It is a significant cultural heritage of the Ottoman (Turkish) ages and still a great opportunity for hiking. A kalderimi may cross the mountains or connect villages with pastures. Some villages in South Crete were accessible only by kalderimi until 1960 (or even 1980). http://en.wikipedia.org/wiki/Kalderimi, http://de.wikipedia.org/wiki/Kalderimi
A kalderimi is suited for pack animals, but not for riding. It is paved, but not suited for vehicles. It is mainly used by hikers, but still also by mules and donkeys. OSM might become a great ressource to collect data on the remains of the kalderimi network.
There is an ongoing discussion on https://help.openstreetmap.org/questions/29888/how-to-tag-a-greek-kalderimi-ancient-mule-path, which I want to refer here. The best proposal after my opinion would be to use an attribute “historic=kalderimi”. Any ideas from the Greek community?