Whale watch sustainably at Kenai Fjords Glacier Lodge.
Whistler, British Columbia
Take a zip line past rebuilt salmon habitats and pristine hiking paths.
New Forest, England
Share the road with cows and ponies in these auto-free tourism villages.
Guanacaste, Costa Rica
Count and protect leatherback sea-turtle eggs.
Ride the river on a nonpolluting houseboat, then dig deep into culture with traditional music and dance lessons.
Track elephant and rhinoceros behavior while staying at this national park.
Help scientists research climate change in the rain forest.
A version of this article appeared in the July/August 2010 issue of Fast Company magazine.