Silversea has four ships in its expedition fleet. Silver Explorer heads to polar regions, Silver Galapagos explores the pristine Galapagos, Silver Discoverer has itineraries in the Pacific, and Silver Cloud is undergoing a major refurbishment to make voyages to Antarctica starting in late 2017.

The Adventure Part: The ships are intimate, with 100 to 130 passengers who will take on activities like Zodiac tours to get ashore on rocky areas in the Galapagos to see boobies, fur seals and turtles, deepwater snorkeling, scuba diving in Indonesia or bird-spotting in Alaska.

The Luxe Part: Cruises on Silversea are all-inclusive: Everything from excursions to drinks are part of the fare. The ships are comfortable, too. Marble suites feature showers decked-out with rainfall shower heads. Plus, there's a spa, beauty salon, a fitness center, and even afternoon tea.

Celebrity Cruises' started with Celebrity Xpedition, a 100-passenger mega-yacht that was purpose-built for the Galapagos and sails the islands 365 days a year on seven- to 15-night itineraries. The Celebrity fleet in the Galapagos grew to three ships in spring 2017 with the addition of 16-passenger Celebrity Xploration and 48-passenger Celebrity Xperience.

The Adventure Part: Go ashore and traipse among the blue-footed boobies, iguanas, turtles, sea lions and pelicans. Peer over the side of your Zodiac as you patrol the clear waters and view schools of colorful reef fish throughout the archipelago. Adventure guides and naturalists lead the voyage, which includes snorkeling, beach walking, and swimming.

The Luxe Part: Recipes are crafted by a Michelin-starred chef using locally sourced ingredients including sustainable seafood. Tuckered out from a day of snorkeling? Order room service in your stylish stateroom. 

Lindblad has a fleet of 13 expedition ships that reach every corner of Earth, from the Amazon, the Caribbean, Patagonia, Europe, Asia and beyond.

The Adventure Part: The line's National Geographic collaboration has been in effect since 2004, providing top-notch scientists and naturalists as guides and you'll find expert instruction on how to shoot better wildlife photos. Excursions include kayaking, stand-up paddleboarding, snorkeling, hiking, Zodiac tours, and diving.

The Luxe Part: The ships feature lounges, pools, and spas offering body treatments, facials, and foot massages.

The French-owner luxury mega-yacht line features expedition itineraries in the polar regions of the Arctic and Antarctica as well as in the Amazon.

The Adventure Part: Naturalist guides lead Zodiac tours exploring Greenland, Iceland, the coast of Russia. Explore fjords, spot polar bears and other wildlife among the ice floes in the Baffin Sea, and head ashore to visit Inuit villages along the Northwest Passage. Or head south on a voyage to interact with penguins or gawk at humpback whales. Amazon journeys take you into mangroves and forests to get up close to howler monkeys, toucans and meet with native tribes.

The Luxe Part: These ships have spa services, fitness centers, and pools, as well as a modern clean aesthetic. Plus, if you book a suite, you get a butler. Can't afford that? Don't worry: Everyone gets 24-hour room service, iPod players, upscale bath products, and French cuisine, including Ladurée macaron cookies and fine cheeses. 

Cross the infamous Drake Passage on Seabourn Quest to explore Antarctica in ultimate style.

The Adventure Part: Expedition leaders curate your journey, leading you on kayaking tours along pristine shorelines and into hidden bays that are home to all kinds of birds — but the stars of the show are the penguins. Wildlife viewings take place on ship and shore, with daily Zodiac landings amid snow-capped volcanoes and glaciers seen while navigating majestic fjords.

The Luxe Part:  You won't believe the range of the massage and spa services available after returning from your forays into the wild. The ship also features a fitness studio, hot tubs, a casino, and spacious suites with verandas and fully stocked bars. Our favorite spot onboard: the Thomas Keller restaurant, a grill and chophouse that elevates classics beautifully. What could be better after a day among the glaciers than a hot fudge sundae?