Tom Mauser came to the U.S. Capitol on Tuesday dressed in gray Vans sneakers, the same ones his 15-year-old son Daniel wore when he was killed by two gunmen at Colorado’s Columbine High School in 1999 along with a dozen other people.Mauser was one of a handful of gun control activists and volunteers who braved a frigid March morning to lay out about 7,000 pairs of shoes on the U.S. Capitol lawn as a makeshift memorial to American children killed by gun violence.Their aim, like the thousands of students across the country who plan to walk out of their classrooms for 17 minutes on Wednesday morning, was to put more pressure on state and federal lawmakers to tighten rules on gun ownership.“There’s nobody in those shoes, it’s like the emptiness in our hearts from gun violence,” said Mauser, 66, of Littleton, Colorado.The memorial, organized by Avaaz, a U.S.-based civic organization, and the National School Walkout, organized by the activists behind the Women’s March in Washington, are part of a grass-roots movement that grew out of the killing of 17 students and staff at a Florida high school a month ago.“I think we’re in the middle of a cultural change in the United States. The majority of Americans want a change in gun laws, and a majority of gun owners want change,” said Emma Ruby-Sachs, deputy director of Avaaz.Many of the proposals favored by gun control advocates, including a ban on assault-style weapons and the closing of loopholes on requiring background checks before gun purchases, are fiercely opposed by the National Rifle Association and its supporters.The 7,000 pairs of donated footwear, arranged side by side in a trapezoid shape outside the Capitol, represent every person younger than 18 who has been killed by a firearm since the 2012 massacre at the Sandy Hook elementary school shooting in Newtown, Connecticut. Actresses Susan Sarandon and Bette Midler, and talk show host Chelsea Handler were among shoe donors. (Reuters)See more news-related photo galleries and follow us on Yahoo News Photo Twitter and Tumblr. read more Disclaimer: Chances are that this post was requested by an advertiser.