The Prussian king followed the trend that had become fashionable among European royalties in the late 18th century by making his private art collection available to viewing by the public. His museum put Berlin on par with Paris, London, and Madrid which contemporaneously established their Louvre, British Museum, and Prado. It has since grown into a collection of five museums in Berlin, all clustered together on the tip of the small island in the River Spree next door to Humboldt.