National Geographic Expeditions runs tours throughout the year for the same price, covering natural wonders like Easter Island and thetropical Daintree rainforest in Australia.
For those who prefer to travel by boat, Wailua Kayak Adventures and Kayak Wailua offer tours that begin with a slow, two-mile paddle down the calm Wailua River, pass an old Hawaiian village along the banks and end in the middle of a tropicalrainforest.