More than a million Americans flooded the streets of cities nationwide for emotional protests demanding tighter gun control, marches spearheaded by teenagers from a Florida high school where 17 people were shot dead last month.
Large crowds also turned out for demonstrations in Atlanta, Boston, Chicago, Dallas, Denver, Los Angeles, Miami, Minneapolis, Seattle and other cities.
According to New York mayor 175,000 people took part in rally.
But the largest protest was in Washington, where organizers said the crowd was estimated at more than 800,000 people, the largest gun control rally in the United States since the million mom march in 2000.
The main stage for the event in Washington was set up near the US capitol and lawmakers were the target audience as speakers delivered blistering warnings that the time has come for stricter gun laws.