George Steinmetz / Corbis

The island state of Papua New Guinea, about 100 miles from the northeastern tip of Australia, remains one of the most unexplored places on dry land. Most of the population is sparsely distributed on the coastal lowlands, while the remote interior contains vast tracts of uncharted rainforest, rugged highlands and extinct volcanoes. Recent scientific expeditions to previously unexplored regions of Papua New Guinea have turned up dozens of previously unidentified species, including spiders, frogs, and a giant wooly rat the size of a large cat. One conservationist who recently went looking for a rare poisonous bird in an unexplored region had to take along a local shaman as a guide, a measure of Papua New Guinea's splendid isolation.

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