With onboard lectures and stops at historic ports, some cruises do double duty: They are a means of transport and portals of academia

American Queen
Line: Majestic America Line
Passengers: 436
Itineraries: Mississippi River
Most folks board a Mississippi riverboat to gamble; those on the American Queen are there for a floating history lesson (they might even feel like they've stepped back into the nineteenth century, given all the antiques on display). This steamboat's Upper Mississippi itinerary runs from Dam No. 1, near Minneapolis, to the confluence of the Mississippi and Illinois rivers, just south of St. Louis. Along the way, Civil War buffs can visit battlefields and literary fans can wander through Mark Twain's boyhood home. The river's centuries of human settlement are traced in shore excursions that take in everything from prehistoric Native American sites to Amish farmland to John Deere's Iowa mansions (800-434-1232; majesticamericaline.com; seven-night Upper Mississippi trip from $1,000).

MV Mozart
Line: Peter Deilmann Cruises
Passengers: 203
Itineraries: Austria, Hungary
Where better to listen to and learn about classical music than along the Danube, the river from which many composers drew their inspiration? The Mozart's Classical Music cruise combines onshore sightseeing by day and onboard concerts at night. If seeing the theater where The Magic Flute was first performed or a piano owned by Beethoven doesn't bring these period works back to life, the evening chamber pieces and sonatas will. Diehards should consider the post-cruise stop in Salzburg, Mozart's birthplace, where passengers will be treated to another concert and can tour two of the composer's childhood homes, now both museums. The Mozart runs other themed educational sailings too, such as an equestrian cruise for the horsey set, with stops at the Spanish Riding School and Bábolna Stud Farm (800-348-8287; deilmann-cruises.com; seven-night Classical Music trip from $1,690).

Oberoi Zahra
Line: Oberoi Hotels & Resorts
Passengers: 54
Itineraries: Nile River
Launched last October, the Zahra is loved by intellectuals and the pampered set alike: The resident Egyptologist will exercise your brain, while the eight Thai masseuses stretch your muscles. What sets this boat apart from the 300-odd others that cruise the Nile is the length of its itinerary—seven nights, instead of the usual three or four, for the 125 miles between Luxor and Aswan, allowing you leisurely afternoons gazing at the Nile's banks. Each guide is assigned to no more than three couples to ensure that passengers aren't slowed down by a large group and have a more individual experience. The Zahra also makes an after-hours stop at Dendarah Temple in the city of Quena, a site not reached by other cruise boats. If possible, arrange your trip to cruise from Aswan to Luxor in order to save the most impressive ruins for last, and don't miss the stop at Aswan's Nubia Museum, which displays artifacts saved from the rising waters of Lake Nasser after the construction of the Aswan Dam (20-2-33-77-3222; oberoizahra.com; seven-night Nile trip, from $1,170).