What the story behind the shoes on the wire?

Starting in the 1970s, at the same time drugs began ravaging urban communities across the country. Throwing a pair of old shoes over the wire was a way for gangs and drug dealers to mark their territory: warning rivals ops they were on enemy territory. Over time, throwing shoes onto neighborhood wires became a global phenomenon—used mostly as a rite of passage for kids, a memorial to victims of violence, or a symbol of celebration, such as graduations or military milestones.