Chania is one of the four regional units of Crete; it covers the westernmost quarter of the island. Its capital is the city of Chania. Chania borders only one other regional unit: that of Rethymno to the east. The western part of Crete is bounded to the north by the Cretan Sea, and to the west and south by the Mediterranean Sea. The regional unit also includes the southernmost island of Europe, Gavdos.