Machen, the U.S. Attorney for the District, will host hundreds of teens at a summit entitled “Breaking the Silence on Youth Violence” on Friday from 3 to 6 p.m. at the Town Hall Education Arts Recreation Campus, 1901 Mississippi Ave. SE. The event is Machen’s first youth summit. Youths age 13-17 are invited to learn about the senselessness of the violence that often surrounds them and enjoy free food and prizes.