Bern (.mw-parser-output .IPA-label-small{font-size:85%}.mw-parser-output .references .IPA-label-small,.mw-parser-output .infobox .IPA-label-small,.mw-parser-output .navbox .IPA-label-small{font-size:100%}Swiss Standard German: [bɛrn] ⓘ), or Berne (French: [bɛʁn] ⓘ),[note 1] is the de facto capital of Switzerland, referred to as the "federal city".[note 2][3] With a population of about 133,000 (as of 2022[update]), Bern is the fifth-most populous city in Switzerland, behind Zürich, Geneva, Basel and Lausanne.[4] The Bern agglomeration, which includes 36 municipalities, had a population of 406,900 in 2014.[5] The metropolitan area had a population of 660,000 in 2000.[6] Bern is also the capital of the canton of Bern, the second-most populous of Switzerland's cantons. The official language is German,[note 3] but the main spoken language is the local variant of the Alemannic Swiss German dialect, Bernese German. In 1983, the historic old town (in German: Altstadt) in the centre of Bern became a UNESCO World Heritage Site.[7] It is notably surrounded by the Aare, a major river of the Swiss Plateau.