Expedition cruiseship operators are reaping the rewards of a growing market as more vacationers seek once-in-a-lifetime adventures instead of repeated trips to the same patches of white sand and blue water.

“If you’ve already been to the Caribbean, you may seek something different,” says Edda Falk, spokeswoman for the Association of Arctic Expedition Cruise Operators (AECO).

“We see a general trend in increased interest in adventure-based tourism.