Riga (Latvian: Rīga, , , ), the capital of Latvia, is situated on the Baltic Sea coast on the mouth of the River Daugava, at . Riga is the largest city in the Baltic states. The Historic Centre of Riga has been declared a UNESCO World Heritage Site, and the city is particularly notable for its extensive Art Nouveau (Jugendstil) architecture, comparable in significance only with Vienna, Saint Petersburg and Barcelona.