peninsula, northern Greece, and a nomos (department) terminating in (east-west) the three fingerlike promontories of Kassandra, Sithonia, and Ayion Oros (Mount Athos). The promontories were once islands, and their isthmuses consequently are composed of loose sediments through which the Kassandra Canal was cut (1937). In antiquity, a canal was dug through the isthmus of Ayion Oros by the Persian king Xerxes I (483-481 BC). The steep sides of the northwest-southeast-trending promontories are the result of recent geological rifting and uplift, and the area is subject to severe earthquakes. The axis of the main Chalcidice Peninsula is composed of the granitic mass of the Kholomon Massif. Sithonia also is composed of ancient rocks; but Ayion Oros terminates in the great marble peak of Mount Athos itself, which is famous for its Byzantine monasteries.
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