In 1939, as he fled to the United States, Robert Capa left behind in his Paris studio a collection of negatives from the Spanish Civil War. His friend, the Hungarian photographer Cziki Weisz, carried them to Bordeaux, where he entrusted them to a Chilean diplomat tasked with placing them safely in his country’s consulate. From that moment on, all trace of the negatives vanished. They would not resurface until seventy years later — in Mexico — revealing 4,500 negatives attributed not to one, but