Up for an unforgettable honeymoon that's romantic, relaxing, and anything but ordinary? With tree house stays so exhilarating you'll never want to climb down, as well as luxurious train trips, here are 12 adventures worth taking.

Kanopi House, Port Antonio
The land of reggae, jerked meats, and a certain substance that vastly improves your mood -- Blue Mountain coffee, that is, mon -- also holds one of the Caribbean's best-kept secrets: four cool little tree houses nestled in its lush northeast coast. These Colonial- and West Indian-style bungalows are perched at a height of about 10 feet. From several of them, you can see the Blue Lagoon, where a natural spring meets the ocean. Each one has a sheltered veranda, complete with a settee for curling up, and a fully loaded iPod with a Bose docking system. (From $300, kanopihouse.com)

What Not to Miss: Floating down the island's Rio Grande river. The four-hour journey, on a raft steered by a man with a bamboo pole, is Jamaica's version of the Venetian gondola ride. Kanopi House will send you aboard with a cooler brimming with chilled Red Stripe beer. And for lunch your captain will pull into an idyllic cove so you can indulge in jerked chicken, curried fish, and rice and beans.

Treehotel, Harads
Mod and avant-garde in a way only the country that brought you Ikea could pull off, these brand-new tree houses are works of art. The Mirrorcube reflects the pines around it; a red house that's ironically called the Blue Cone; and the Cabin (left), with its entrance on the roof, were designed by a handful of architects. All are elevated between 12 and 20 feet off the ground and look out over the traditional village of Harads to the Lulea River. In typical Scandinavian fashion, Treehotel also has a sauna -- only it's a circular pod hoisted seven feet up. Rent it out to spend a steamy, eucalyptus-scented evening in the air. (From $500, treehotel.se)

What Not to Miss: Stay up all night to see if the midnight sun really never sets. Travel right around the summer solstice, the longest day of the year; in 2011 it falls on June 21. The hotel offers a middle-of-the-night horseback excursion through the awe-inspiring countryside, followed by an early-morning meal of hot chocolate and waffles with cloudberries and cream.

Daintree Eco Lodge & Spa, Daintree
Heed the call of the wild at this lodge deep in the world's oldest rain forest (it's been around for an astounding 135 million -- yes, million -- years). The boutique property is fronted by a glassy freshwater lagoon and is rife with the indigenous flavor of the nearby community of Kuku Yalanji. Aborigines inspired many of the details, including the names of each bungalow, which are based on the animals or plants that live around it ("walbul walbul" means "butterfly," while "karrkurr" is "green tree frog"). The stilted rooms are surrounded by ferns, palms, and native ginger, and they boast screened balconies and local artwork. Pack your hiking boots -- there's plenty of exploring to do, and it's best done by foot. (From $536, daintree-ecolodge.com.au)

What Not to Miss: The couples' Tropical Exotics treatment on the spa's private outdoor deck consists of an exfoliating scrub, a cleansing face mask, and a conditioning hair treatment, and winds down with a body-butter massage and soothing milk bath.

El Capitan Canyon, Goleta
At this coastal retreat just north of Santa Barbara, only a canvas wall stands between you and the wilderness. But the permanent safari tents are a far cry from your Girl Scout days: Each sits on a raised wooden platform and is furnished with a handmade willow bed frame, storage trunk, and writing desk, plus a private picnic table, grill, and fire pit outside. Spend your days relaxing by the water (the Pacific is less than a mile away; just hop on a beach cruiser and pedal down) or at the Creekside Canyon Spa, whose treatment rooms are spread between cabins and tents surrounded by gardens of honeysuckle, jasmine, and lavender. (From $135, elcapitancanyon.com)

What Not to Miss: A meal cooked by a "camp butler." Ditch the charcoal and lighter fluid for an evening, and have him whip up a dinner of tri-tip, baked beans, and s'mores. Then toast your new beginning with a bottle of Happy Camper merlot from El Capitan's market.

Amanwana, Moyo Island
You'll make quite a splash when arriving at this ultra-posh hideaway. The eight-seat seaplane that puddle-jumps from nearby Bali lands directly in the cerulean bay, then motors up to the dock. Once ashore, settle into one of 20 tents, either surrounded by jungle or fronting the Flores Sea. They feature teak walls, glass windows, and peaked canvas roofs, and have air-conditioning, plush chaises, and a king-size bed fit for a royal couple. Lounge by the freshwater dipping pool, or browse through the extensive CD library and mellow out in the open-air music pavilion. Then peel yourself away from all that luxury to give windsurfing a shot in the warm waters. (From $700, amanresorts.com)

What Not to Miss: Turtle Street, a reef ledge to the north of the camp, where green and hawksbill turtles cruise by in the leisurely current (along with eels and whitetip reef sharks). Whether you scuba or snorkel, just be sure to take the plunge.

Baja Camp, Isla di Espiritu Santo, Baja California
Our neighbor down south is a time-honored honeymoon favorite. But this isn't your typical sand-and-sun vacation (though it does involve loads of both). Baja Camp's tents are pitched right next to the ocean on an otherwise uninhabited island that's home to only a few curious ringtail cats, a herd of wild goats, some cacti, and -- most important -- more than a dozen beaches. Kayak to secluded inlets, get to know the resident sea lion colony, and trek around the dunes. After the sun dips down, you'll sit family-style around a table lit with oil lamps to dine on fresh seafood with the other guests. (All-inclusive rates from $480 per tent, bajacamp.com)

What Not to Miss: Alone time on a secluded stretch of sand. A guide will drop you off with beach chairs, a big sun umbrella, snorkeling gear, and a fully stocked cooler of refreshments. You'll feel like castaways -- but with enough provisions for a fiesta.

Honolulu Sailing Company, Maui and Lanai
If you two are Gilligans when it comes to boating but love to be out on the water, look no further than this jaunt from the west coast of Maui to the pineapple isle of Lanai and back. For five days, the 43-foot sailing yacht will be all yours, save for a handful of at-your-service crew members. Along the way, you'll drop anchor at secret snorkel spots and hidden beaches where you'll be able to try your hand at stand-up paddleboarding (a sport recently given a go by celebrities including Kate Hudson and Jennifer Garner). When you're feeling adventurous, see if you can rustle up some grub by spearfishing -- the onboard chef will cook your catch for dinner. (From $5,000 per couple, honsail.com)

What Not to Miss: A mouthwatering meal at the Four Seasons Resort Lana'i at Manele Bay. It's an excuse to slip on some heels on dry land and treat yourself to dishes such as pan-seared Hawaiian sea bass.

Star Clippers, Grenadine Islands
On this eight-day cruise, you'll have the opportunity to hunt out pirate haunts on Barbados, snorkel the crystalline waters of the Tobago Cays, and practice your French on Martinique. But don't let the word "cruise" fool you -- rather than an enormous ocean liner, your island shuttle is a tall ship (complete with five sky-high masts) called the "Royal Clipper." It accommodates just 227 people, which means when you're not exploring the 12 ports of call, you'll have plenty of room to roam. Soak up some rays at one of three pools, listen to the tropical beats of the steel-drum band, cheer on crab races, and eat your meals in a three-story dining room bathed in natural light. (From $1,975 per person, excluding island excursions; starclippers.com)

What Not to Miss: The views! For the most breathtaking panoramas, check out each of these three spots: the crow's nest at the tippity-top of the main mast; the bowsprit net, which is suspended above the ocean; or one of the "hidden balconies," which are positioned to look like they're jutting out over the water and are perfect for staking out sunsets.

Odysseus Cruising, Gulf of Gokova
Even if you've never heard of the Gulf of Gokova, know that it's referred to as the Turkish Riviera for a reason -- namely, dramatic coastline, perfect coves, and charming villages. This private cruise will introduce you to its deep blue waters in style. It'll be just you two, the captain, a chef, and a pair of stewards on a 75-foot "gulet," historically a fishing boat, for eight days. While onboard, you might jump in for a swim, then take a catnap on deck. If you start feeling restless, you can request to go ashore wherever you choose. Standouts include Bodrum, a seaside town frequented by jet-setters, and the 4th-century ruins of Cnidus, with Greek temples and great views. (All-inclusive rates from $7,500 per couple, odysseuscruising.com)

What Not to Miss: The island of Sedir, where local tall tales say Cleopatra and Mark Antony spent their honeymoon. And apparently she refused to tread on any land that wasn't Egypt, so Antony had sand shipped over from her homeland (aww) and poured on the isle's beach.

Via Rail, Toronto-Jasper-Vancouver
On this nine-day traverse across the Great North (one of the best out there for epic scenery and affordability), you don't have to worry about cabin fever -- the trip tacks on plenty of excursions. It includes a one-night hotel stay and activities in Toronto, with its high-rises and hip neighborhoods; two nights in the mountain town of Jasper; and yet another in gorgeous Vancouver, tucked between the Pacific Ocean and a backdrop of mountains. The ride itself, on the "Canadian," winds around the Great Lakes, past boreal forests, over expansive prairies, and through mountain passes; the regionally based food changes with the terrain. (From $3,119 per person, including hotels, cartantours.com)

What Not to Miss: A good soak at the Miette Hot Springs. Head to the steamy pools during your downtime in Jasper to unwind amidst the peaks of the Canadian Rockies. If you're lucky, you may even spot a bear in the distance.

Venice Simplon-Orient-Express, Venice-Prague-London
This historic train is so well preserved, it looks like it was lifted right out of the 1920s -- and a lot of it actually was. Sleek cabins are outfitted with inlaid mahogany and mother-of-pearl. And the bar car, complete with a baby grand and a pianist who takes requests, serves up a mean martini. The five-day itinerary lets you relish a few days in Prague, where you'll need to book a room for two nights; then you're off to London (first passing through Frankfurt and Paris). During onboard meals, you'll stuff yourself on French cuisine prepared by talented chefs in a kitchen about the size of a walk-in closet. (From $3,920 per person, excluding hotel; orient-express.com)

What Not to Miss: A lazy paddle down Prague's Vltava River. After you've checked out the city's castle (founded more than 1,100 years ago), wandered around Old Town, and snapped a few shots of the postcard-worthy Charles Bridge, make your way to the tiny river island of Zofin. There, you can rent a rowboat to see the sights from the water.

Rovos Rail, Cape Town-Pretoria-Victoria Falls
Boldly go where most of your friends have probably never gone before. This six-day caper starts in a cosmopolitan city and ends at some of the world's most breathtaking waterfalls. Your carriage is the Edwardian-style "Pride of Africa." Plush rooms hold either convertible sofa sleepers or double beds, plus the ultimate extra: en-suite showers (practically unheard of in train travel). The trip includes a night in a hotel in the bustling city of Pretoria, as well as day trips to spots such as the historic diamond town of Kimberley, where De Beers still has an operating mine. But the falls themselves are the real prize; the mile-long curtain of water will quicken your pulse almost as much as your I do's did. (From $3,765 per person, including hotel, rovos.com).

What Not to Miss: Outside the cities, a twinkling blanket of stars covers the sky after dark. Sit on the open-air balcony to take it all in as the train chugs through the tranquil Karoo Desert.