About four-fifths of Greece is mountainous, including most of the islands. The most important range is the Pindus, which runs down the center of the peninsula from north to south at about 2,650 m (8,700 ft) in average elevation. Mt. Olympus (Ólimbos; 2,917 m/9,570 ft) is the highest peak and was the legendary home of the ancient gods.
Greece has four recognizable geographic regions. The Pindus range divides northern Greece into damp, mountainous, and isolated Epirus (Ipiros) in the west and the sunny, dry plains and lesser mountain ranges of the east. This eastern region comprises the plains of Thessaly (Thessalía) and the "new provinces" of Macedonia (Makedonia) and Thrace (Thraki)—"new" because they became part of Greece after the Balkan wars in 1912–13. Central Greece is the southeastern finger of the mainland that cradled the city-states of ancient Greece and comprises such classical provinces as Attica (Atikí), Boeotia (Voiotia), Doris, Phocis, and Locris. Southern Greece consists of the mountainous, four-fingered Peloponnesus (Pelopónnisos), separated from the mainland by the Gulf of Corinth (Korinthiakós Kólpos). Islands of the Aegean comprise the numerous Cyclades (Kikládes); the Dodecanese (Dhodhekánisos), including Rhodes (Ródhos); and the two large islands of Crete (Kríti) and Euboea (Évvoia).
Greek rivers are not navigable. Many dry up in the summer and become rushing mountain torrents in the spring.