Charley Kline (left), working at UCLA, sent the first transmission over ARPANET to Bill Duvall at the Stanford Research Institute. Guy Raz/NPR hide caption

itoggle caption Guy Raz/NPR

A Marine with with Fox Company of the 2nd Battalion, 8th Marine Regiment carries a metal detector at the front of his patrol in Helmand province in southern Afghanistan near Garmsir. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR