In Calexico, Calif., schools crack down on students who live across the border.
Readers share their picks.
Along a 12-mile stretch, border patrol agents say a zero-tolerance plan has resulted in a 78 percent decrease in arrests.
Anthropologist Brian Fagan uses Earth’s distant past to predict the crises that may lie in its future.
A young conscript vividly describes how combat made him a hardened veteran.