Between 1947 and 1950, the anthropologist Herbert Dick led an archaeological party to the "Bat Cave", in New Mexico, known to have been a site for primitive agriculture. There, he and his team dug through the layers of ancient rubbish and excrement until they found a collection of popcorn: shelled cobs, loose kernels and husks. Right at the bottom they found some tiny, primitive kernels which, when carbon-dated, proved to be 5,600 years old.
They then took a few of the unpopped kernels, dropped them in hot oil, and watched. They still popped perfectly. There is no record of whether any of the group tried the popcorn - though given the trouble they'd taken to find these precious kernels, it seems unlikely.
<a href="http://lifeandhealth.guardian.co.uk/food/story/0,,2153737,00.html">Full Story</a>