It's like a giant chunk of chalk tumbled out of the sky, shattering on to a sparkling, turquoise glass floor.
As we glide through the John Hopkins Inlet, rugged mountain ranges dusted with snow, multi-coloured rock faces and bear-filled forests reflect in the smooth waters, splattered with slabs of pearly ice which form tiny islands where seagulls converge in the rare autumn sunlight.
Some cruisers stand alone, huddled in blankets and glaring into the scenery, mesmerised, while others balance against a stairwell, attempting to get the perfect shot of Margerie Glacier.
"Lose yourself in these surroundings and maybe you too will find an inner connection with the land," says our ranger, in a tone so soothing she reminds me of a hypnotist.
It's hard not to be hypnotised by the serenity of Glacier Bay.
Time stands still and the silence is broken only by camera clicks and the faint firework-like sound of carving - seemingly small pieces of ice "actually the size of a jaguar" breaking off the glacier and crashing into the bay.
Margerie's sheer size is majestic, but what's striking is the electric blue that seeps through its crevices. It's a unique hue caused by "vibrational energy transitions" - when sunlight hits the ice and red and yellow wavelengths are absorbed, while blue makes it through. "Call it that if you want but because this blue's only seen in glacial ice, I call it magic," enthuses the ranger.
A day earlier I snagged a close-up look at the magical blue while crunching along the Herbert Glacier in Juneau.
It's 8C and sunny as we touch down on the ice with Coastal Helicopters, then wander around, dodging 300m chasms. Up close, the electric blue is almost glowing against the blinding, white ice. Feeling like I've stepped into a winter's fairytale, I don't think twice before foregoing everyday sanitary rules and filling my cupped hands with "must-try" water from a small fissure, the chill numbing my fingers long after I've slurped down the glacial refresher.
Helicopters aren't the only way to get a bird's eye view of Juneau. Steps away from the cruise dock, Mount Roberts Tramway shoots us 550m up through rainforest to the Mountain House, where hikers can find endless trails past twisted western hemlock trees, kids can meet bald eagle Lady Baltimore and art enthusiasts can browse local works. All-you-can-eat crab plus blueberry zinfandel from Alaskan winery Bear Creek awaits in the Timberline Bar and Grill.
"This is the best view of Juneau without buying a plane ticket or helicopter ride," says Joann Flora, who moved to Alaska 36 years ago.
"They say once you've been here you'll always come back and I see that again and again with people who have moved lock, stock and barrel to the lower 48 [states] and are back in six months. People just decompress in an environment like this. It's a feel-good spot."
Back on board the Westerdam, between crafting monkeys out of towels, room attendant Adi's surprised our day's stories involve sunshine. "Sunny in Juneau? Never happens!" he chuckles.
Yet we luck out again in Sitka, a small town where wildlife enthusiasts can tick bear-spotting off their Alaskan bucket list at Fortress of the Bear, a non-profit sanctuary housing rescued/rehabilitated bears.
"We've given them pineapple, so they're a bit hyper," explains naturalist Erin, as we observe sibling black bears Smokey and Tuli playfully chasing each other.
The pair were orphaned when their mother was shot two years ago, but today they're happily at home in Sitka.
The city is also home to the Alaska Raptor Centre, but with our seven-night sojourn nearing its end, there's still much of our ship to explore, from its mini-mall, casino and nightclub to art auctions, photo-editing workshops, mixology classes, cooking demos and pub quizzes. Then there are the nightly shows, from Dancing with the Stars: At Sea (where cruisers compete to represent the Westerdam at a Holland America Line "Champion Cruise") to the standout performance of "junk rock" band Recycled Percussion, a blood-pumping show straight from Las Vegas.
As a kid, Justin Spencer's parents wouldn't The Westerdam in Glacier Bay (left); the John Hopkins Glacier (top); Mt Roberts Tramway.Photos: Travis Jacobs, Ian D. Keating
buy him a drum kit, so he instead emptied the kitchen of pots and pans. Now he's turned that passion into an interactive show transforming power tools, buckets and ladders into percussive beats, with audiences members handed drumsticks, pots and earplugs on arrival.
Nonstop activities, shows and food are enough to make you reluctant to leave the boat, but we swap the Vista-class ship for a different kind of boat in Ketchikan, the salmon capital of the world.
Hopping on Ketchikan Duck Tours' land-roving, sea-cruising "amphibious vessel", we whiz past stair streets, totem poles and 29 bars (one for each church, due to local legislation stating bars can't outnumber churches) and stop by the town's prized salmon in a river described as a "buffet" for local bears. About 1500 of them supposedly spend hours also scuffling through bins, prompting locals to "bear-proof" them with bungy cords.
Although the ship's fridges are stocked up in Seattle, chefs take advantage of the Ketchikan stop by picking up fresh fish for the afternoon's long-awaited salmon bake, a poolside barbecue serving up melt-in-your-mouth Alaskan salmon.
I'm not one to argue with seafood for breakfast, lunch and dinner but there are endless other options on board, whether at poolside burger joint The Dive-In, fine dining spot Pinnacle Grill, Italian restaurant Canaletto or the lavish Vista Dining Room. Meanwhile, the all-day, buffet-style Lido Deck offers everything from Thai, sushi, Indian and roast lamb to a different type of eggs benedict for every day of the week.
It only takes a fleeting final stop in Victoria to realise that, as sumptuous as the grilled lamb ribs and tuna poke at Old Town spot Little Jumbo are, the ease of having boundless options and five-star service just steps away from our cabin back on board, is difficult to sacrifice.
How does one avoid masses of weight gain while living on a cruise ship?
"You just keep adjusting your uniform," chuckles Captain Bart Vaartjes, over cocktails at the Atrium Bar. "Try and take the stairs ... I walk for an-hour-and-a-half around the ship with my son everyday."
Captain Vaartjes joined Holland America Line 18 years ago, having known he wanted to sail since he was six. He also met his wife on board. "When the salt gets into your veins, it's there to stay. And we're here with 2000 people and not one is out to have a miserable time.
"Everyone's here to have fun. We walk around and see only smiling faces."
Helloworld has a deal on a seven-night Alaskan cruise, taking in Glacier Bay. The Nieuw Amsterdam departs Vancouver on May 6 for a round trip. Interior staterooms start at $1439pp with balcony staterooms at $2299pp (both twin share). Meals, entertainment onboard, port charges and fees included.