The island is mostly mountainous, and its character is defined by a high mountain range crossing from west to east. It includes Crete's highest point, Mount Ida, and the range of the White Mountains (Lefka Ori) with 30 summits above 2000 metres in altitude and the Samaria Gorge, a World Biosphere Reserve. Crete forms a significant part of the economy and cultural heritage of Greece, while retaining its own local cultural traits (such as its own poetry and music). The Nikos Kazantzakis airport at Heraklion and the Daskalogiannis airport at Chania serve international travelers. The palace of Knossos, a Bronze Age settlement and ancient Minoan city, is also located in Heraklion.