An international team of scientists has managed, for the first time in history, to selectively modify individual molecules, breaking or forming bonds between their atoms at will. The advance will make possible the creation of hitherto unimaginable molecules, according to the Spanish chemist. Diego Pena, one of the leaders of the group. “This technique is going to revolutionize chemistry,” he says. Your investigation It's the cover of the magazine Science, a reference for the best world science.