In 1964 a graduate student named Donald Currey was studying the old bristlecone pines near Wheeler Peak in Nevada, working out the Ice Age from their rings. One gnarled tree was hard to sample, and the Forest Service gave permission for it to be cut down. Back in the lab he counted the cross-section and got more than 4,800 rings. It was the oldest living thing anyone had yet found, and until that summer it had been standing on the mountain. Nobody did it out of malice; the tree simply looked no more remarkable than its neighbours, which is what bristlecones always look like. The odd thing about age is that it barely shows from outside. The only way anyone could be certain how old that tree was turned out to be the one way that also meant it would never get any older.