Potsdam, on the Havel River just 25 km southwest of central Berlin, is the capital and crown jewel of the federal state of Brandenburg. Easily reached by S-Bahn, the former Prussian royal seat is the most popular day trip from Berlin, luring visitors with its splendid gardens and palaces, which garnered Unesco World Heritage status in 1990. Visit Schloss Sanssouci, the private retreat of King Friedrich II (Frederick the Great), who was also the mastermind behind many of Potsdam's other fabulous parks and palaces. Most miraculously it survived WWII. Schloss Cecilienhof was chosen for the Potsdam Conference of August 1945 to lay the groundwork for Germany’s postwar fate.