Greece, officially the Hellenic Republic, is a country in Southeast Europe, situated on the southern tip of the Balkan peninsula. Greece shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to the east. The Aegean Sea lies to the east of the mainland, the Ionian Sea to the west, and the Sea of Crete and the Mediterranean Sea to the south. Greece has the longest coastline on the Mediterranean Basin, featuring thousands of islands. The country consists of nine traditional geographic regions, and it has a population of nearly 10.5 million. Athens is the nation's capital and largest city, followed by Thessaloniki and Patras.
Greece is considered the cradle of Western civilization, being the birthplace of democracy, Western philosophy, Western literature, historiography, political science, major scientific and mathematical principles, theatre, and the Olympic Games. From the eighth century BC, the Greeks were organised into various independent city-states, known as poleis (singular polis), which spanned the Mediterranean and the Black Sea. Philip II of Macedon united most of present-day Greece in the fourth century BC, with his son Alexander the Great rapidly conquering much of the known ancient world, from the eastern Mediterranean to northwestern India. The subsequent Hellenistic period saw the height of Greek culture and influence in antiquity. Greece was annexed by Rome in the second century BC, becoming an integral part of the Roman Empire and its continuation, the Byzantine Empire, which was predominantly Greek in culture and language. The Greek Orthodox Church, which emerged in the first century AD, helped shape modern Greek identity and transmitted Greek traditions to the wider Orthodox world. After the Fourth Crusade in 1204, Latin possessions were established in parts of the Greek peninsula, but most of the area fell under Ottoman rule in the mid-15th century. Greece emerged as a modern nation state in 1830, following a war of independence.
Over the first hundred years, the Kingdom of Greece sought territorial expansion, which was mainly achieved in the early 20th century, during the Balkan Wars and up until its Asia Minor Campaign ended with a catastrophic defeat in 1922. The short-lived republic that followed was beset by the ramifications of civil strife and the challenge of resettling refugees from Turkey. In 1936 a royalist dictatorship inaugurated a long period of authoritarian rule, marked by military occupation during World War II, civil war, and military dictatorship. Greece achieved record economic growth from 1950 through the 1970s, allowing it to join the ranks of developed countries. Democracy was restored in 1974–75, and Greece has since been a parliamentary republic.
Greece is a democratic and developed country with an advanced high-income economy, the second largest in the Balkans, where it is an important regional investor. A founding member of the United Nations, Greece was the tenth member to join the European Communities (precursor to the European Union) and has been part of the eurozone since 2001. It is also a member of numerous other international institutions, including the Council of Europe, NATO, the OECD, the WTO, and the OSCE. Greece has a unique cultural heritage, large tourism industry, and prominent shipping sector. The country's rich historical legacy is reflected in part by its 19 UNESCO World Heritage Sites.