Basel is the global center of the pharmaceutical industry, but most travelers visit for the world-famous ART Basel festival, as well as the numerous art galleries, iconic architecture and museums.

Philadelphia, the birthplace of American democracy, offers visitors a rare opportunity to walk through the very streets where the nation’s founding ideals were debated, signed, and set into motion. The city's art scene is as bold as its history. The Philadelphia Museum of Art is home to works by Van Gogh, Duchamp, and an entire Japanese teahouse, but it might be better known for the "Rocky Steps" out front, where visitors recreate the famous movie scene daily.

Coimbra, set along the banks of the Mondego River in central Portugal, is a historic city known for its academic legacy and old-world charm. Once the medieval capital of Portugal, it is home to the University of Coimbra, one of the oldest in Europe and a UNESCO World Heritage Site.

You'll know why picturesque Grenada is known as the "spice island" when you notice the scent of nutmeg, vanilla and cocoa in the air. Grenada's waterfalls, lush rain forests, volcanic crater lake, tiny villages, cocoa, nutmeg and banana plantations, rum distilleries, scenic hiking trips, pristine coral reefs, and hidden-away unspoiled beaches all make Grenada one of the most popular ecotourism destinations for those who like to discover off-the-beaten-track natural beauty and charm.

Whether cruising along its waters, exploring historic towns, or simply soaking in the scenic views, the Rhine River offers an experience that is as diverse as the countries it passes through.