From whales in Alaska to boab trees in Australia, nature's finest sights are just a sail away, writes Kaye Holland.
Alaska
Wildlife abounds in Alaska's untamed wilderness. Look out for the Big Five: bears, moose, dall sheep, caribou and wolves. Bald eagles soar overhead, whales breach in the sea and salmon make a dramatic journey upriver every summer to their spawning grounds.
The Galapagos Islands
The Galapagos offer cruise passengers the chance to get up close to wildlife, from penguins, giant tortoises, sea lions and marine iguanas to birds including mockingbirds, blue-footed boobies and Galapagos hawks.