Polykastro is a town and a former municipality in Kilkis regional unit of Central Macedonia, Greece. Since the 2011 local government reform it is part of the municipality Paionia, of which it is a municipal unit, and the seat. The municipal unit has an area of 312.717 km², the municipal unit 45.775 km².
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Greece is a country in southeastern Europe with thousands of islands throughout the Aegean and Ionian seas. Influential in ancient times, it's often called the cradle of Western civilization. Athens, its capital, retains landmarks including the 5th-century B.C. Acropolis citadel with the Parthenon temple. Greece is also known for its beaches, from the black sands of Santorini to the party resorts of Mykonos.

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