Sixty Hours in the Dark

In May 1952, Rosalind Franklin positioned a fine fiber of hydrated DNA before an X-ray beam in her laboratory at King's College London. The exposure took over sixty hours — silent, patient work in a dimly lit room, capturing what no human eye could see. When the image finally emerged, it revealed a striking X-shaped pattern of dark spots: Photo 51, the clearest X-ray evidence yet of DNA's helical structure.…