Talk about being on top of the world. A three- or four-week cruise (say, between New York and Anchorage, or Greenland to Russia) traverses the sounds, straits, and seas that link the Atlantic and Pacific oceans, with dramatic icy landscapes and visits to Inuit villages. This is a route only the most intrepid explorers of the past could even dream of taking, with Roald Amundsen and his team being the first to successfully navigate it in a trip that took three years. Now, more than 100 years later, luxury expedition ships will take you on this journey. Crystal Serenity will make the trip in August, with planned shore excursions that include kayaking around icebergs and camping on an ice sheet in Greenland. These once-in-a-lifetime journeys have also been offered by Ponant, Silversea, Lindblad Expeditions, and Quark Expeditions.

Long-awaited cruises to Cuba are finally on the horizon, with Carnival Corporation’s Fathom brand offering cruises with a social and cultural bent (as still required by U.S. federal law) beginning in May. Weeklong sailings will call on historic Havana, the island’s capital, as well as Cienfuegos and Santiago de Cuba, with opportunities to explore the country’s impressive fortresses (some of which date back to the 16th century), cathedrals, and mansions, plus its national parks and rich musical and culinary traditions. 

Myanmar, also known as Burma, was closed off to visitors for five decades until the borders were opened in 2011. The tourism industry is slowly growing, especially along the Irrawaddy River. Two-week cruises typically depart out of Yangon, and include journeys to many of the country's elaborate temples as well as visits to villages and markets. Many of the major river cruise lines, including AmaWaterways, Avalon, Scenic, and Viking, are now offering small-boat cruises.

The revered rivers of ancient India overflow with spiritual significance as well as utilitarian importance, from bathing and washing clothes to a burial place for the dead. To cruise along one of India's rivers is to see the country in all its multifaceted beauty and harshness, and lately more lines are getting in on the exotic action. A handful of river cruise lines, including Pandaw, G Adventures, Haimark Travel, and Uniworld, offer one- to two-week Ganges River trips, to or from Kolkata (Calcutta). Other areas that occasionally see cruises include the rivers of Kerala in the south (known as "backwaters") and the Brahmaputra River in the northeast.

In November 2015, the Carnival Corporation opened a new cruise port called Amber Cove on the north coast of the Dominican Republic. This marked the first time in nearly 30 years that a major cruise line called on this part of the Caribbean island. In the 25-acre Amber Cove there is a town square plus markets, bars, restaurants, and a pool with private cabanas for rent. Yet while the new port was designed to keep cruisers busy, docking here opens the whole Puerto Plata region up for exploring, from beaches and golf courses to tours of rum factories and the 16th century Spanish Fort San Felipe. Carnival calls here year-round, and other lines including Princess and Holland America visit, too. And when it's not in Cuba, Fathom's Adonia will also call at Amber Cove for voluntourism shore excursions (including water filtration, forest reclamation, and education projects).