Photo 51: Rosalind Franklin's astoundingly clear x-ray diffraction photograph of DNA taken in 1952 which showed the telltale double-helical signature of DNA. The photo received perhaps the ultimate pop cultural accolade when it became the basis for "Photograph 51", a star power-driven play with Nicole Kidman playing Franklin.
This photo is fascinating in many ways, perhaps most controversially because Franklin's supervisor Maurice Wilkins (who she saw not as a supervisor but as an equal) showed it to James Watson without his knowledge: in Watson's account, when he saw it his "jaw dropped and pulse raced". The pieces swirling around in his and Francis Crick's mind fell in place and the rest was history.
The image is also very intriguing because it points to one of the great what-ifs of scientific history. Franklin was undoubtedly the best DNA crystallographer in the world and there was nothing anywhere else that came close to the clarity of this work, so the tantalizing question is: how soon would she have hit on the idea of a double helix herself? My guess is, not too soon. As wronged as Franklin was by the male establishment and history, she was stubborn and defensive and not very open to other fields, especially chemistry and model-building, the two fields which mattered the most for nailing down the solution to the puzzle. Feeling besieged by the men around her, she was loath to collaborate. Much more than any raw brilliance, Watson and Crick's biggest quality was their willingness to do whatever it takes and beg, borrow, ask - and steal - from any field necessary to crack the structure. In the parlance of Isaiah Berlin's parable, Franklin was a hedgehog, Watson and Crick were foxes.
If she had lived Franklin *should* most definitely have shared in the Nobel Prize for the discovery of the helix: whether she *would* have is another of the what-ifs of history, although given the male domination of the prizes it seems unlikely. Sadly history silenced the question: Franklin died in her 30s of cancer, an iconic figure to generations of future scientists and female scientists in particular.