Ηalkidiki is a peninsula in the eastern part of the province of Macedonia in northern Greece and is one of the regional units of Greece. The autonomous Mount Athos region constitutes the easternmost part of the peninsula but not of the regional unit. The capital of Ηalkidiki is the main town of Polygyros located in the centre of the peninsula. The Cholomontas mountains lie in the north-central part of Ηalkidiki. Ηalkidiki consists of a large peninsula in the north-western Aegean Sea, resembling a hand with three “fingers”, though in Greek these peninsulas are often referred to as “legs”, named Cassandra, Sithonia and Agion Oros. Ηalkidiki borders on the regional unit of Thessaloniki which is the second biggest city in Greece in the north.