Far from being stationary objects, Alaska's glacial formations are active and powerful. Winding down from mountains and fjords, these massive rivers of ice are often on the move, some dropping enormous chunks into the sea, a process known as calving. A cruise journey allows you to get up close to these behemoths of nature and see the incredible spectacle of ice towers crashing into the ocean.
Alaska has more than 100,000 glaciers, about half of the world's total. An Inside Passage journey will show you some of the biggest and best, like Hubbard Glacier, which at 122km in length is the longest ocean facing glacier in Alaska. Glacier Bay National Park, spanning 1.3 million hectares, is a stunning network of inlets that channel the frozen tide towards the sea. College Fjord is home to 16 ocean facing glaciers while Tracey Arm Fjord is awe-inspiring with its snow-capped mountains and steep granite walls.
The Alaskan authorities, for the sake of conservation and limiting overcrowding, imposes certain restrictions on cruise lines when it comes to visiting both Hubbard Glacier and Glacier Bay.
Forget about boring stretches of ocean where the most action you'll see in the water is the white crest of a small wave - the Inside Passage is buzzing with life. Humpback whales make something of a splash when they're around and during the summer months more than 2000 of these gargantuan sea creatures are known to frequent Alaskan waters. Orcas and beluga whales are just as abundant in Alaskan waters, as are dolphins, who like to show off their acrobatic tricks near ships.
Seals, sea lions and otters congregate on chunks of ice or frolic, while the salmon-rich waters are welcomed by brown bears, who enjoy them as a tasty snack. Flocks of seabirds make for some great bird-watching too, with the star of the show being the majestic bald eagle.
As well as top-notch wildlife viewing, cruising in Alaska also serves up a range of action-packed adventures off the ship. Take a sightseeing tour over the magnificent terrain in a helicopter or small plane - clients can even get the chance to stand on the surface of a glacier. Or fly even further north of Alaska to check out the Arctic Circle.
Go hiking in the wilderness with a ranger or on a self-guided trip in one of the national parks, such as Denali National Park. Embark on a driving adventure with a guide and journey through the diverse terrain in search of wildlife, or take the reins on the ground with a spot of dog-sledding. Make a splash with a few hours of white water rafting or a jet boat ride through the glacier-fed rivers. And for something a little more sedate, throw a line in the river and see if you can hook yourself a plump salmon.
Of course, there are also the country's charming port towns to discover, like the tiny state capital Juneau, and the towns of Skagway, Ketchikan and Sitka with their Alaskan gold rush ambience.