Thousands in Barcelona march shouting "I'm not afraid!"

BARCELONA, Spain — Hundreds of thousands of peace marchers flooded the heart of Barcelona on Saturday shouting "I'm not afraid" — a public rejection of violence following extremist attacks that killed 15 people, Spain's deadliest in more than a decade.Emergency workers, taxis drivers, police and ordinary citizens who helped immediately after the attack on Aug. 17 in the city's famed Las Ramblas boulevard led the march. They carried a street-wide banner with black capital letters read