The legendary Mississippi flows north to south through the middle of America, and is the fourth largest river in the world. In its lower reaches it passes through sleepy river towns, Southern cities, and plenty of Civil War history. Cruises are available virtually year-round, and include experiences on classic-style steamboats that explore the stretch between New Orleans and the "Blues City" of Memphis, or run round-trip from New Orleans. The route brings you to antebellum mansions and places like Natchez, oozing Southern charm. You'll want to spend time in both the "Big Easy" and Memphis, where attractions include the National Civil Rights Museum and Elvis's Graceland. Other highlights en route include Oak Alley Plantation, which looks straight out of "Gone With the Wind," and the Civil War battlefields at Vicksburg National Military Park. There are also river-side casinos in several places.