10 of the world's most adventurous cruises

Over at Big Island adventurous vacationers can get aboard the Safari Explorer with just 36 others and, in between kayaking and dolphin spotting, engage in a mesmerizing ballet with manta rays.

Over at Big Island adventurous vacationers can get aboard the Safari Explorer with just 36 others and, in between kayaking and dolphin spotting, engage in a mesmerizing ballet with manta rays.