Orchilla Lighthouse is at the western end of the island and is the most westerly point in Europe. Back in AD 150, the Greek geographer Ptolemy thought it was the end of the world. In the 17th Century it became the point of the Longtitude Zero Meridian. This did not change until the 1880s when the point was moved to Greenwich. The island is still someimes referred to as the `Isla del Meridiano`.