Nationwide, hundreds of thousands demand gun control

Crowds of people hold signs Saturday on Pennsylvania Avenue in Washington, D.C., at the “March for Our Lives” rally in support of gun control. (Alex Brandon/AP Photo)

WASHINGTON — In a historic groundswell of youth activism, hundreds of thousands of teenagers and their supporters rallied across the U.S. against gun violence Saturday, vowing to transform fear and grief into a “vote-them-out” movement and tougher laws against weapons and ammo.