While many European capitals are coastal or river-basin cities, Madrid sits on a high plateau known as the Meseta Central. At an average elevation of 667 meters (2,188 feet) above sea level, it is the highest capital city in the European Union. Located in the dead center of the Iberian Peninsula, Madrid was chosen as the capital in 1561 by King Philip II because of its central location, which helped unify the diverse regions of Spain. The city is famous for its 'Golden Triangle of Art,' home to three world-class museums: the Prado, the Reina Sofía, and the Thyssen-Bornemisza. Madrid's Royal Palace is the largest functioning royal palace in Europe by floor area, with over 3,400 rooms. Despite its inland location, Madrid is home to the second-largest wholesale fish market in the world (Mercamadrid), trailing only Tokyo, thanks to an incredibly efficient transportation network that brings fresh seafood from the Spanish coasts every morning.