The Alps (/ælps/;  French: Alpes [alp]; German: Alpen [ˈalpn̩]; Italian: Alpi [ˈalpi]; Romansh: Alps; Slovene: Alpe [ˈáːlpɛ]) are the highest and most extensive mountain range system that lies entirely in Europe,[2][note 1] separating Southern from Central and Western Europe and stretching approximately 1,200 kilometres (750mi) across eight Alpine countries (from west to east): France, Switzerland, Italy, Monaco, Liechtenstein, Austria, Germany, and Slovenia.[3] The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening  caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn. Mont Blanc spans the French–Italian border, and at 4,810m (15,781ft) is the highest mountain in the Alps. The Alpine region area contains about a hundred peaks higher than 4,000 metres (13,000ft).