Back in 1942, as German bombs fell on London, Donald and Betty Smith got married. They decided to honeymoon in the University city of Cambridge and headed for the railroad terminus where Betty, foolish woman, purchased a rock bun to sustain her on the journey. She took a single nervous nibble. That was enough. The rest of the hideous bun lingered in her handbag, uneaten. The couple took it home, put it in a cupboard. Forgot about it through sixty years of married bliss. They’re dead now. But, catch this -- the bun isn’t, and it has just come to light again, rediscovered in that cupboard. And the dratted thing isn’t even mouldy. Why? That is what food technology experts at Cambridge University are now seeking to discover. Mr and Mrs. Smith’s family have presented the scientists with the rock bun so that science can unravel the mystery of its longevity. Food doesn’t usually last long unless it’s pickled in alchohol or frozen solid. But we regular railroad users already reckon we know the answer…. The British railroad rock bun is almost certainly made of rock. You have been warned.