Interlude from a previous life WASHINGTON, Sept. 18 — Newly discovered traces of ancient roads, bridges, and plazas in Brazil’s tropical forest may help dispel the once-popular impression of an “untouched” Amazon before the Europeans’ arrival. In southern Brazil, archaeologists have found the remains of a network of urban communities that apparently hosted a population many thousands strong. Reporting their findings in the journal Science, published by AAAS, the science society, the researchers say the people who dwelled there dramatically changed their local landscape.