Uniworld's elegant 130-passenger River Empress is the riverboat version of a luxury cruise ship. Impressionist-style paintings and damask upholstery pretty up the main lounge while the restaurant is retro chic, thanks to eye-catching red leather chairs, green water glasses, and sketches of jazz-age scenes. There is an impressive scope of diversions onboard, especially for a river ship, including a gym, spa, and library, plus an expansive sundeck for gazing at the scenery as the vessel glides along the Rhine, Danube, and Main rivers.