Thousands of protesters converged on Washington DC to call for tighter gun laws
Students from Parkland, Florida, where 17 people died in a mass shooting last month, joined them
There was a minutes-long silence by Parkland survivor Emma Gonzalez
An 11-year-old girl, Naomi Wadler, got one of the biggest cheers as she spoke about inner-city gun violence
Hundreds of cities organised affiliated marches, including London, New York, Sydney and Los Angeles
George Clooney and Kim Kardashian were among celebrities who took to the streets of the nation's capital
Remarkably, cities around the world are also holding marches calling for tighter gun laws in the US.
London, Sydney and Geneva are among the locations.
Image source, AFPA "die-in" outside the US Embassy in London
Image source, AFPSydney, Australia
Image source, EPAGeneva, Switzerland
Image source, AFPWashington DC
Image source, ReutersMiami, Florida
Image source, Getty ImagesProtesters gathered early in Washington
Movements have sprung up in the aftermath of the Parkland school shooting, with students rejecting what has been dubbed the "new normal" for their generation.
Thousands of teenagers, including many still too young to vote, have become grassroots activists. Social media has become a tool for their ideas and campaigns to spread.
Their calls for gun control are not different to those in the aftermath of other tragedies - but the maturity and voracity of the students publicly voicing their demands has led many on social media to say this time feels different.
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Hundreds of thousands of people across the US are expected to attend rallies in support of more restrictive gun laws.
The largest protest will be in Washington DC, where demonstrators will gather on the main street between the White House and Congress.
There are also dozens of rallies and events planned around the world.
The BBC has been speaking to people about why they are marching.