Designed by mega-architect Frank Gehry, this stunning contemporary art museum is swathed in a mass of billowing “sails” of glass, giving the impression that it is about to sail off into the lush greenery of the Bois de Boulogne, a large park on the western edge of the city. Once you’ve taken in the arty outside, you have two choices: (1) stand in line to see the sophisticated temporary collections of ultra-contemporary art, or (2) go explore the Bois de Boulogne’s alleys, gardens, and lakes. If you choose the former, be sure to buy an online ticket in advance: You’ll get a time slot, which will considerably reduce the time you spend in line. If you are not big on heady modern and conceptual art, you should probably stick to option number 2.