DISCOVER Vol. 23 No. 5 (May 2002)Table of Contents The Amazon Trail Anna Roosevelt's ventures into the jungles of South America have turned up traces of human settlements far older than archaeologists ever suspected By John Dorfman Photography by Jennifer Tzar Archaeologists visiting remote sites in Brazil must rely on the skills of local pilots to locate—and land on—small airstrips in the rain forest. "The pilots here are very good," says Roosevelt, a veteran Amazon explorer, because the mining industry depends on them. "When I have a goal," says Anna Curtenius Roosevelt, her voice emphasizing the word, "everything else is...