Peacock groupers, spotted sweetlips and orangespine unicornfish -- oh my! Learn to dive among and identify these and hundreds of other colorful critters while you conduct marine research in the world's third-largest coral-reef system. With Blue Ventures' six-week volunteer program, gather scientific data along the southwest coast of Madagascar in an award-winning, United Nations-recognized operation. After discerning and measuring coral species on the ocean floor, you'll work together with local communities and nongovernmental organizations to develop long-term plans for conserving the reef and improving the quality of life in surrounding fishing villages. When you aren't mapping a new reef or helping establish a sustainable cucumber farm, visit the nearby baobab forest, take Malagasy language lessons and teach English to the local Vezo children. Bed down in beach bungalows overlooking a turquoise lagoon outside the petite town of Andavadoaka, and fall asleep counting fish. blueventures.org
- Blue Ventures' six-week program rates from $3,797.