Crick and Watson's DNA Double Helix Model

The plates you see represent the four bases, adenine, thymine, guanine and cytosine, cut to shape in the Cavendish Laboratory workshop, and the rods stand for the sugar and phosphate backbone. Watson and Crick fitted the pieces together by hand, testing which shapes could pair, and it was the discovery that adenine always matches thymine and guanine always matches cytosine that made the structure work. The original model was dismantled and its parts scattered; this reconstruction was made in 1977 by Farooq Hussain at King's College London using some of the original plates, so parts of what you see are the very metal they handled.

The discovery drew on X-ray photographs taken at King's College by Rosalind Franklin and Raymond Gosling, especially the famous Photograph 51, which Watson was shown without Franklin's knowledge. She died in 1958, before the Nobel Prize was awarded to Crick, Watson and Maurice Wilkins in 1962. The model now stands close to other objects that changed the modern world, a reminder that a few pieces of tin can carry an idea that reshapes medicine and biology. A memorable detail is the crude workshop finish of the plates, cut quickly because the two men were in a hurry.

Did You Know? The plates were cut so hastily in the Cavendish workshop that some still show file marks; the builders were racing rivals in California.