Image by John Freeman Getty Images

The Greek temple–style Old National Gallery is a three-storey showcase of 19th-century European art. To get a sense of the period's virtuosity, pay special attention to the moody landscapes by Romantic heart-throb Caspar David Friedrich, the epic canvases by Franz Krüger and Adolf Menzel glorifying Prussia, the Gothic fantasies of Karl Friedrich Schinkel, and the sprinkling of French and German impressionists.