The Eagle - originally the Eagle and Child - is a Grade II listed public house and the second oldest pub in Cambridge, after the Pickerel Inn on Magdalene Street. The street front on Bene't Street dates from around 1600, with a galleried 19th-century wing tucked behind, facing a small courtyard. For more than three and a half centuries the building has done what English pubs do: served students and shopkeepers, weathered fashions in food and beer, and absorbed the small dramas of everyday life. The galleried courtyard is one of the last surviving examples of its kind in Cambridge, a reminder of when coaches stopped here and travellers slept upstairs.

During the Second World War the back room became known as the RAF Bar. American and British airmen stationed nearby - the East Anglian airfields were thick with bombers and fighters - drank here on leave, and a tradition emerged: climb on a chair, take a lighter or a lipstick or a Zippo, and burn or write your squadron number and name on the low ceiling. Hundreds of names accumulated. After the war the ceiling was preserved deliberately, and it is still there - black candle-smoke letters and numbers crowding the plaster, a kind of overhead memorial to the airmen who passed through. Many of those signatures belong to men who did not survive their next mission. You order a drink, look up, and read.

James Watson and Francis Crick worked at the nearby Cavendish Laboratory, and they ate at the Eagle often enough that the staff knew their table. On 28 February 1953 they walked in and Crick made his now-famous announcement. The anecdote is told in Watson's book The Double Helix and is the reason the pub today serves a special ale called Eagle's DNA. Also in 1953, at the same table, Watson and Crick drew up a list of the 20 canonical amino acids over lunch - one of the founding documents of molecular biology, sketched out on whatever napkin or scrap was to hand while the pints arrived. Science can happen in a laboratory. It can also happen between bites of a ploughman's.

The first blue plaque went up on the exterior wall in 2003. It named only Watson and Crick. From 2017 onwards, visitors began adding Rosalind Franklin's name in graffiti to the plaque - a public correction of the historical record, since Franklin's X-ray crystallography images had been crucial to the breakthrough. The graffiti was removed; it kept reappearing. In 2023 the plaque was finally replaced with a new one that names Franklin and Maurice Wilkins alongside Watson and Crick. The original plaque is now preserved in the Whipple Museum of the History of Science on Free School Lane, a few minutes' walk away - a small artefact of how scientific credit is given, taken, and eventually corrected by a public that refused to forget.