O Teixadal de Casaio is the second largest and most western yew forest in Europe. It is nestled in a valley in the Serra do Eixe, with Pena Surbia rising behind it. The highest mountain in Galicia, Pena Trevinca, is nearby.During World War II, Nazi Germany operated a wolframio mine in the area. A significant group of resistance fighters hid in the forest from Franco and the Guardia Civil after the Spanish Civil War. Remnants of this “Cidade da selva” can still be found in the forest. There are approximately four hundred yews in O Teixadal, the oldest around four hundred years old. Yews can live over two thousand years old and every part of the tree is toxic to humans and animals, except for the berry surrounding the seed.