Oceanwide Expeditions draws passengers from the U.S., Europe, Canada, Australia, Japan and China, all of whom share a passion for exploration, nature and wildlife. Expect to meet people in their mid-40s to mid-60s. Younger travelers are more prominent on the most adventurous sailings, and it's not unusual to see fit cruisers in their 70s and 80s on any sailing. (Children must be at least 3 years old to sail.) Solo travelers are welcome, though the line does charge a single supplement for solo cabins, or you can request that the line find a roommate for you.

No. The vibe onboard is casual. Plan to dress for comfort and warmth rather than to impress.

Shore excursions, usually by Zodiac and including helicopter rides on MV Ortelius, are included. On select cruises, the company provides rubber boots in your size with advance notice. For "basecamp" cruises, camping gear and kayaking are included, as well. Transfers, internet service, laundry, wine with meals, drinks at the bar and gratuities are extra. The onboard currency is euro.

An Oceanwide Expeditions cruise is all about wildlife and nature, and the cruise line programs its itineraries to give you access to as many landings by Zodiac as weather conditions permit. All of the activities offered are popular, including guided Zodiac sailings, hiking, kayaking and snowshoeing. Camping overnight in Antarctica is popular among the hardiest cruisers.

Oceanwide Expeditions also has an onboard helicopter on certain itineraries aboard MV Ortelius. And helicopter excursions on those sailings are in high demand.

Best for: Hardy, super adventurous types who don't mind pitching in to haul kayaks or pitch a tent

Not for: Anyone with an aversion to hourslong hikes and snowshoeing; anyone who can't navigate a steep gangway