THE Wall. Its icy ramparts stretch for miles, towering 400 feet. The granite-grey ice at its foot is fully four centuries old. As you approach, it’s impossible not to think of Wildlings, of White Walkers, of The Night King. Such is the grip of Game of Thrones.

But this isn’t Westeros, despite the evocatively named Disenchantment Bay below. Nor is it a swords and sorcery fantasy. This is Alaska’s mighty Hubbard Glacier, the largest tidewater glacier in North America at 76 miles long and 1,200 feet deep.

And it’s probably the No 1 attraction on the wish-list of everyone who books a cruise among the icebergs and floes up here.

Off the coast of Yakutat, 200 miles North-West of Juneau, Hubbard is huge, more than six miles wide where it meets the ocean. The breathtaking blue face is up to 400 feet tall, and when it calves, as it often does, icebergs four stories high are not uncommon.

It is, of course, in retreat as rising temperatures take their toll, fuelled by our lack of care of the planet.

Ironic, isn’t it, that while we all fear for the glacier’s global warming fate, we all live for that photograph when ice crashes into the sea below?

Each time Hubbard calves, there’s a rumble like thunder, delayed by the distance the sound has to travel.

As we sail ever closer, what starts as a misty grey strip grows and grows in stature until, half a mile away – we’re not allowed any closer – it glistens in beautiful blues and tantalising turquoise.

We’re in good company. Seal families float sedately past on breakaway ice floes; sea otters float lazily on their backs, watching our progress. Eagles fly overhead, snatching errant fish.

It’s a scene that will be repeated next day as Star Princess sails into Glacier Bay, home of natural wonders lorded over by magical Margerie Glacier.

Captain Stefano Ravera, a former Italian Navy special forces seaman, works with the pilot to turn the giant cruise liner smoothly in circles, offering the best photo opportunities.

We’ve sailed from Whitter on the second leg of a Land & Sea package that has already seen us amid the scenic splendour of bear country in and around Denali National Park.

Now, we’re heading south on the last cruise of the season before winter ice exerts its inexorable grip on the seaways.

And, at each port of call, a new Alaskan adventure awaits.

In Skagway we board the White Pass Railway, one of the world’s great train journeys, winding its way from the coast up along the Gold Rush trail into Canada’s Yukon.

The tracks cling precariously to the mountainside, passing over perilous-looking trestle bridges that could grace a Road Runner cartoon.

Read more: Riding the White Pass gold rush train into the Yukon

We hang out of the open-air viewing platforms on the back of each carriage, autumn’s graceful gold gradually turning ice-grey as we climb ever upward.

The border between the USA and Canada is marked by a modest customs station, flags of both nations fluttering in friendship.

Our destination is Carcross, more specifically the Caribou Crossing Trading Post where we feast on barbecued chicken, potatoes and slaw, followed by doughnuts.

It’s a strange little place that’s fascinating, if a little touristy, with a modest museum, sled dogs, husky puppies, goats and alpacas.

This is unforgiving country, though, on the train back we pass the graves of men killed building the railroad many thought nigh-impossible.

Next day, we sail in to Juneau as the fog rolls in off the sea. It’s an evocative scene, but a double-edged one.

We meet with photographer Brian Hild, who has swapped the world’s war zones for landscapes in one of the world’s most beautiful backdrops.

He takes us to gaze out over the mighty Mildenhall Glacier, but that freezing fog scuppers our chances of the afternoon’s whale-watching expedition. That’ll have to wait another day.

And that day is tomorrow. After docking in Ketchikan, we set out to sea again in Captain Clay’s small fishing boat, accompanied by his dog, Manny.

It’s Manny’s first time out with guests, and five of us fuss him mercilessly. But enough of that, we’re on a mission – to land the catch that we’ll dine on later that evening.

We’re in search of halibut, and we manage to land one, alongside a skate, and a clutch of sharks a couple of miles or so out to sea.

The quiet, when the boat’s engines are turned off, is breathtaking. Then it’s broken suddenly, spectacularly, by a passing humpback whale.

It is absolutely THE magical moment of the two-week cruise. And we have it all to ourselves – six humans and one seadog.

We celebrate with Denali-brewed beer from the ice bucket. It’s a day we all know we’ll never forget.

That evening, the chef on Star Princess cooks our catch and serves it to us, with the great ceremony it deserves, in one of the ship’s splendid restaurants.

We iron the creases out of our Alaska Sport Fishing, Hunting and Trapping Licenses. There aren’t many of those back home in Blighty.

While our thoughts are on food, we muse over the wide selection of restaurants on our floating hotel.

There’s Sabbatini’s, a fine dining Italian eaterie; the signature Crown Grill where they take steak seriously; the silver service Capri Dining Room; a pizzeria, ice cream parlour, a patisserie…

As we left Glacier Bay a few days back we’d dined at the Chef’s Table, a special privilege that included Champagne and hors d’oeuvres in the galley before a six-course feast in the Capri Room.

It included a sumptuous take on ‘Surf & Turf’ comprising lobster tail, diver scallops, lamb chop and herb-crusted venison loin, with mustard hollandaise, berry rosemary jus and drawn butter, fresh market vegetables and roasted chateau potatoes.

And, yes, that was just one of those six courses. It’s available as a premium price extra on the cruise, showcasing the very best the kitchens can offer.

Star Princess – now reborn as P&O Australia ship Pacific Encounter – also boasts a full-sized theatre staging productions worthy of Broadway and the West End, and a relaxing spa – I recommend the hot stone massage.

There are swimming pools, a library, a coffee bar that’s a people-watching paradise, an art gallery and any number of nightclubs and bars, including a wine cave where we take wine-blending lessons with the friends we’ve made on our cruise.

Our stateroom is comfortable with all mod cons, a queen-sized bed, a sofa, chairs, coffee table, wi-fi and movies on demand. The balcony is ideal for private glacier viewing, or watching the dolphins that play around the ship’s bow each day.

The only thing missing is tea and coffee facilities, not a must for the American cruise market. Still, get a coffee loyalty card early on your cruise, and simply nip down the glass elevators in the atrium to satisfy your caffeine fix.

The many members of crew and staff we meet are unfailingly pleasant and polite without standing stiffly on ceremony. This is a friendly ship, far removed from the traditional starchy image many mistakenly have of cruising.

Read more: If you see a bear, don’t run. If you see a moose, vamoose!

And, of course, that’s part of the appeal. You’re well looked after, pretty much everything is included in your fare (although, of course, premium dining, excursions, spa treatments and shopping are extra) and you have the comfort blanket of the ship to return to after each day’s energetic exploration.

When we disembark at Canada’s stylish Vancouver at the end of the holiday, we’ve explored Alaska on land and sailed more than 1,700 miles south from Whittier. 

Along the way we’ve made new friends, ticked off several items on the travel bucket list and made memories that will last a lifetime.

What’s not to love?

Read more: When you’re rafting in Alaska and hear a backwoods banjo…

• I was a guest of Princess Cruises during a land and sea cruise package in 2017, and a version of this feature previously appeared in national and regional newspapers including the Sunday Mirror.
• For forthcoming Alaska cruises with Princess, set sail to www.princess.com