James Watson (AFP)

Cambridge, April 14 (Reuters): If walls could talk, what a story the Eagle pub would tell.

From a 16th Century coaching inn to a hang-out for British and American airman during World War II, Cambridge’s most famous watering hole has played host to travellers, tradesmen, tourists and a fair share of academics and students.

But its finest hour, and the one which has gone down in the history books, was on a winter day 50 years ago when two scientists working at Cambridge University’s Cavendish Laboratory burst through its door and announced that they had discovered the secret of life.

James Watson, a rangy 24-year-old American, and Briton Francis Crick, 36, had unravelled the three-dimensional structure of deoxyribonucleic acid, better known as DNA, the molecule that contained the human genetic code.

It turned out to be the biggest scientific discovery of the 20th Century, an achievement that set the stage for future advances in biology, medicine, agriculture, pharmaceuticals and forensics.

So where better to reveal it than their favourite pub?

“They came rushing in through this door,” said Sian Crowther, the Eagle’s current manager, pointing to a side entrance from the courtyard to one of the oldest parts of the 500-year-old building. “This was the first place that they actually announced it.”

Earlier that Saturday morning in late February in his laboratory, a stone’s throw from the Eagle where he regularly lunched with Crick, Watson had shifted around cardboard cut-outs of the components of DNA, like piecing together a jigsaw puzzle, to work out how they fit together.

When Crick arrived he knew the double helix model of DNA, resembling a twisted spiral staircase, was the answer and could eloquently explain how hereditary information is stored, replicated and passed on to the next generation.

Watson has admitted that he thought Crick’s announcement that day in the Eagle seemed a bit immodest, particularly in a country like England, known for its understatement.

“I felt slightly queasy when at lunch Francis winged into the Eagle to tell everyone within hearing distance that we had found the secret of life,” Watson wrote about that famous day.

Half a century later it is evident that Crick was right.

But it was not until their research was published in the science journal Nature on April 25, 1953, that the larger scientific community and the world became aware of the discovery.

Nine years later they were awarded the Nobel Prize.

To mark the golden anniversary of the discovery, Watson, now president of Cold Spring Harbor Laboratory in New York, will revisit his old stamping grounds for a series of celebrations in the quaint university city where it all happened.

The Eagle pub will play a prominent role in the festivities when Watson is expected to unveil a plaque at the pub on April 25 to mark its role in the discovery.

Tourists aware of its significance already make pilgrimages to down a beer, or something stronger, while sitting in its low-ceilinged, timbered rooms gazing through stained glass windows across Benet Street or out onto the side courtyard.

“We get people coming specifically to the pub for the DNA connection,” said Crowther, who is preparing for the dignitaries, academics and media who are expected to descend on the pub for Watson’s anniversary visit.