A Cruise Director shares the essentials for formal nights, day excursions, what not to wear—and the one item travelers forget most.

Spending over 100 nights on a cruise ship might not be for everyone. But for those who long to see the world from pole to pole or sea to sea, these once-in-a-lifetime journeys may be just the thing.

Norovirus is hardy and can resist acid conditions (like those in the gut) and moderate temperatures (at which we wash clothes ...