In Western Greece, the Kefalonia – Ithaca UNESCO Global Geopark is an island complex belonging to the Heptanese (from the Greek for seven, the number of principal Ionic islands). Kefalonia occupies an area of 773 km² and is home to 35,801 inhabitants and Ithaca’s 117 km² are inhabited by 3,084 people. The geopark is rich in geosites of karstic origin such as caves, sinkholes and underground streams, all of which are scattered throughout the islands telling of a geological history that goes back more than 250 million years. Both islands are located very close to a mountain chain shaped like an arc (the Hellenic arc) formed by the subduction of the African Plate under the Eurasian Plate. It is the most tectonically active region in Europe. The geopark also has a literary significance as Kefalos and Ithaca are named in the Odyssey as the homeland of Ulysses, the hero of Homer’s epic poem. The geopark is also home to prehistoric Hellenistic and Roman monuments, medieval castles, Byzantine and post-Byzantine monasteries, traditional settlements, windmills, bridges and lighthouses, a rich cultural heritage scattered over the area’s extraordinary geological features.