One of the greatest and most beautiful examples of European rococo, Sanssouci was built between 1745 and 1747 as Frederick’s summerhouse, a place where he could let his wig down, discuss weighty matters with French philosopher Voltaire, and make music with composer Carl Philip Emanuel Bach. In short, Sanssouci (“without cares”) was a sort of summer resort for an enlightened monarch. The king loved it so much that he requested to be buried there—and in fact, that’s his grave right in front of the palace. (Why are there potatoes on it instead of flowers? Fred’s supposedly the one who introduced Germans to the humble spud, arguably his most long-lasting accomplishment.) Atop a gorgeous terraced vineyard, the long, one-story building is crowned by a dome and flanked by two round pavilions. On a 45-minute audio tour (available in English), you’ll be able to wander through its restored halls, from the elliptical white-and-gold Marble Hall to the ornately rococo Music Room to the Voltaire Room, where the philosopher slept surrounded by fanciful bird and flower decorations. Amazingly, the palace survived both World War II bombing and the GDR unscathed. The East German government, normally disdainful of anything Hohernzollern, even lobbied for it to become a UNESCO world heritage site. (It did, in 1990.) Fred the Great created the original design for the grounds, and his planning still is evident in the restored vineyard terraces and the area immediately around the palace.