Portugal is a country located in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe and is bordered by the Atlantic Ocean to the west and south and by Spain to the north and east. The Atlantic archipelagos of the Azores and Madeira are also part of Portugal. Mainland Portugal is split by its main river, the Tagus. The northern landscape is mountainous in the interior with plateaus indented by river valleys, whereas the south, that includes the Algarve and the Alentejo, features mostly rolling plains and a climate warmer and drier than in the north. The Algarve, separated from the Alentejo by mountains that reach altitudes up to 900m in Pico da Foia, has a climate much like the southern coastal areas of Spain. Portugal's highest point is Mount Pico on Pico Island in the Azores. This is an ancient volcano measuring 2,350 m (7,710 ft).