Königsallee, Dusseldorf’s poshest shopping street, is also an official historic landmark. Developed in the early 19th century, the grand boulevard is graced by a central moat lined with chestnut trees. Window-shop the luxe stores, such as Cartier and Louis Vuitton, plus a few more affordable retailers. When you need a break, stop for coffee at an outdoor café and watch the fashionable passers by.