Part of the mystery of Utah’s disappearing monolith may have been solved. Although it’s still unclear how or why the 12-foot steel structure appeared in the first place, one man says he witnessed its sudden removal. Ross Bernards, 34, was visiting the monolith Friday night when, he said, four men arrived and pulled down the sculpture. He told The New York Times that the men started shoving the monolith from side to side as they tried to uproot it, and one of the men was overheard by Bernards saying: “This is why you don’t leave trash in the desert.” The men broke the structure apart and carried it off in a wheelbarrow, he recalled. “As they walked off with the pieces, one of them said, ‘Leave no trace,’” Bernards said. The scene was caught on camera by Bernards’ friend.