Seeing the world by cruise ship is better than ever.

Why? Cruise lines are offering more of the world.

After decades of plying the Caribbean, the Mediterranean and the Pacific, cruise lines are listening to their well-traveled customers who have no interest in another swirl around the same old sea, with calls in the same old ports.

They're adding new ports, new adventures.

Credit for the changes goes to new shipbuilding techniques, which have made remote parts of the world accessible, and the popularity of European river cruising, which offers access to new waterways and towns that are short on fame but long on delight. Hundreds of new ports have opened in the past decade, with small cities such as Melk, Austria, and Akaroa, New Zealand, popping up on itineraries.

New adventures abound:

  • On a Windstar cruise, you can watch the volcano Stromboli spew fire against the night sky off the coast of Italy.

  • Azamara's small ships often stay in port late into the night, giving you a chance to sample tapas in Barcelona or throw down the dice in Monte Carlo.

  • The hottest small-ship cruises of 2014? Antarctica and Peru's Upper Amazon. Very little space remains, and 2015 trips are booking now.

    Here's a roundup of what's new and what's hot. (Don't say you weren't warned about making reservations now.)

    RIVER CRUISES

    The Rhine factor

    European river cruises are a hot ticket, with head counts for summer and fall cruises already high.

    Why the rush to the river?

    People like river cruising for the easy access to shore; often the port city is just footsteps away. And then there's the appeal of smaller, yet historic European cities such as Heidelberg and Cologne, Germany, and Strasbourg, France. Also, themed cruises, such as tulip cruises in the Netherlands and Christmas market cruises, target specific sites more efficiently than most land travel could.

    Surely the popularity is also partly due to Viking River Cruises' fairy-tale commercial on "Downton Abbey." The announcer's mellifluous intonations about castles on the Rhine seem to flow right from the PBS script.

    In mid-March, Viking River Cruises reports its summer and fall European river cruises as being more than 50 percent booked. And that's with 14 new longships plopping into European waterways March 18. Viking's Rhine cruise remains hugely popular.

    For 2015, Tauck is even suggesting the whole family sail past the castles of the Rhine together. Sound like one pricey family trip? Tauck CEO Dan Mahar terms the company's river cruise bookings as "phenomenal" and suggests booking now to get desired cabins for 2015.

    Besides Tauck and Viking, three other cruise lines -- Avalon Waterways, AmaWaterways and Uniworld Boutique River Cruises -- sail the Rhine, Rhone, Seine, Elbe, Main and Danube rivers. Viking also sails the Douro in Portugal.

    New Asia routes

    The Mekong River has also proved to be a good thread, tying together travel in Vietnam and Cambodia. AmaWaterways, Avalon River Cruises, Viking River Cruises, Uniworld Boutique River Cruises and Orient-Express all offer that trip.

    Myanmar is also explored by Orient-Express' 2013 launch, Orcaella, sailing the Chindwin River from Mandalay to the Himalayan foothills. Orient-Express' Road to Mandalay has long sailed Myanmar's Ayeyarwady River.

    SMALL SHIPS

    In the Amazon

    Remote parts of the world, such as Peru's Upper Amazon, have become accessible just in the past few years to people who lack croc-wrestling skills. Sedate adventurers can sip pisco sours from air-conditioned cabins on a small ship, watching for freshwater pink dolphins and braving the occasional jungle trek.

    Just a few years ago, this region belonged to jungle-crawling adventurers. Now boutique ships Aria Amazon, Aqua Amazon, Delfin I and Delfin II, carrying in the range of 22 passengers, boldly sail these waters.

    Todd Smith, founder of Tahoe City-based AdventureSmith Explorations, explains that shallow drafts -- with the ship sometimes only extending 5 feet into the water -- allow sailing close to shore and in shallow waters.

    That means travelers to Baja California can watch whales in their feeding and breeding grounds; those visiting Papua New Guinea can cruise over shallow sandbars; and those in Alaska can sail up close to view glaciers and gamboling grizzly cubs.

    Alaska, Australia

    Small-ship cruising in Alaska is increasingly popular for the access and ability to avoid the large ships, often clustered in a harbor, essentially nullifying Alaska's silent splendor.

    Australia's Kimberley is a fascinating region attracting small-ship travel. Located in the northern part of Western Australia in a largely uninhabited, unvisited and uncharted region of giant cliffs, stunning gorges and waterfalls, the region is also home to petroglyphs at least 20,000 years old. Called the "Bradshaw" or Gwion Gwion cave paintings, the dancing figures are charmingly animated, looking something like the head-flinging figures in the original iPod commercials.

    MAINSTREAM LINES

    Down Under is big

    In the past five years, Australia and New Zealand cruises have become popular, with all the mainstream lines establishing routes in the region, including Holland America, Princess Cruises, Royal Caribbean, Carnival, Norwegian Cruise Line and Celebrity Cruises.

    New cruise ports have made New Zealand a destination unto itself, with big ships able to call at Tauranga, Napier, Port Chalmers, Dunedin, Picton and Akaroa.

    It's a real money-saver to cruise both nations, since the flight to the Southern Hemisphere is so costly, and the nations are more than 1,500 miles apart.

    New Asia focus

    Two mainstream lines -- Holland America and Princess Cruises -- both sail extensive Asia routes in 2014 and 2015; Holland America also sails Southeast Asia, Thailand, Indonesia, China and Japan. Princess Cruises has been targeting the Japanese market with its expanded Asia offerings, and its Japan cruises are intriguing.

    European offerings

    Sailing the Norwegian fjords is an increasingly popular trip on Holland America and Crystal Cruises. Holland America even heads into the Arctic Circle on June and July 2014 sails. (Hurtigruten, a Norwegian line that offers fewer amenities, also makes weekly trips up the Norwegian coast into the fjords, delivering mail to small Norwegian towns as it goes.)

    The bonus of a Norwegian fjord cruise in fall/winter may be a good show of the Northern Lights, which are just moving off the peak of an 11-year cycle.

    Princess offers a series of 12-day cruises in the British Isles in 2015, a dandy way for Americans to get around all the bases. Traveling England, Scotland, Wales and Ireland by land and air would cost a fortune in time and money.

    Holland America has two cruises in summer and fall of 2015 to Scotland and Ireland.

    Anne Chalfant's cruising app on iTunes is "Cruise! A Guide to Ships and Trips." On Google Play, it's "Cruise! Hands-on Guide." Chalfant is a former travel editor of the Contra Costa Times.