Thousands of pairs of shoes were placed on the lawn in front of the US Capitol on Tuesday to mark every child who has been killed due to gun violence since the 2012 Sandy Hook massacre, wrote dailymail.co.uk

According to global advocacy group Avaaz, which organized the protests, 7,000 pairs of shoes were collected for the 'Monument for our Kids' memorial to bring 'the heartbreak of gun violence to Congress' doorstep'.

Though most of the shoes were collected in a two week period, some were donated by families who lost their children to gun violence.

The organization also said that some celebrities donated shoes as well, including Chelsea Handler, Alyssa Milano, Bette Midler, and Susan Sarandon. 

One of the parents who attended the protest on Tuesday was Tom Mauser, whose 15-year-old son Daniel was killed in the 1999 Columbine shooting. 

He wore the gray Vans his son was wearing when he was shot.

'I'll be traveling to DC literally wearing my son Daniel's shoes, the ones he wore the day he died at Columbine,' Mauser said in a press release before the event. 

'I think this kind of event with shoes offers a very powerful metaphor both for how we miss the victims who once filled those shoes, and also for how we see ourselves wanting to walk in their place, seeking change, so that others don't have to walk this painful journey.'

Event organizers claimed the 7,000 pairs of shoes - 14,000 shoes altogether - symbolized the 7,000 children killed in the US between December 14, 2012 and March 13, 2018.

According to a press release issued in advance of the event, the figure of 7,000 came in part from an American Academy of Pediatrics study. 

Although there was no link to any figures or date, Avaaz said the study found that guns kill an average of '1,300 American kids a year'.

Between the Sandy Hook massacre and the US Capitol protest, about five years and three months have passed. The figure used by Avaaz would amount to approximately 6,825 children killed by guns in that time period.

The memorial comes the day before the scheduled national student walkout to protest gun violence following the Parkland, Florida, high school shooting last month.

Students all over the country plan to walk out of school for exactly 17 minutes at 10am local time to honor the 17 people who lost their lives at Marjory Stoneman Douglas High School. 

It also comes ahead of the March For Our Lives protest on March 24 during which students will take to the streets of Washington, DC to protest gun violence and advocate for measures of gun control 

The Parkland shooting was the deadliest school shooting since 26 - 20 students and six teachers - were killed in 2012 at Sandy Hook Elementary School in Newtown, Connecticut.