First came the tree, all 19.5 metres of it, with roots and branches and leaves. Then, weeks later, the discovery of 150 fossilised logs, one on top of the other, a short distance away. Nikolas Zouros, a professor of geology at the University of the Aegean, couldn’t believe his luck. In 25 years of excavating the petrified forest of Lesbos, he had unearthed nothing like it. “The tree is unique,” he said. “To discover it so complete and in such excellent condition is a first. To then discover a treasure trove of so many petrified trunks in a single pit was, well, unbelievable.” Stretching across almost all of the Greek island’s western peninsula, the petrified forest, a Unesco global geopark, is among the largest in the world. … “The more we discover the more we understand past ecosystems,” he said.