Colombian activist César López came up with a striking new peace symbol in 2003 — the escopetarra, a guitar fashioned from a gun.

The word combines the Spanish escopeta (shotgun) and guitarra (guitar). López made the first from a Winchester rifle and a Stratocaster; he’s since built four more and given them to various Latin American artists and cities and to the United Nations, which displayed it at a disarmament conference.

López told the BBC that he got the idea when he saw a soldier carrying his weapon like a guitar. “From there sprang the idea of joining the worst invention of mankind can be joined with the most beautiful,” he said. “Some of the AK-47s have the barrels marked with each of the victims. So we mark the barrels with the songs we play.”