There is much that the armchair conservationist can do to help save endangered species — anything from donating to groups like Conservation International to buying sustainable wood products approved by the Forest Stewardship Council. But if you have the means, your eco-dollars may be better spent taking a vacation. Ecotourism — sustainable travel that is built around observing wild animals, not disturbing them — provides vital revenue for many local communities in wildlife-rich areas. And a steady stream of tourists can help convince people in biological hotspots like Madagascar or the Brazilian Pantanal that the local wildlife is worth more alive than extinct. For visitors, the prize is a firsthand study of the extinction crisis: you can't really understand what the world is at risk of losing, until you've come eye-to-eye with an indri lemur or a ploughshare tortoise. As Conservation International president Russell Mittermeier says, "You've got to see it to save it." Following are five places his group suggests your visit can make a real difference.