The Tower of Hercules is one of the oldest lighthouses in the world. It's located off the coast of Galicia in northwestern Spain. It dates to Roman times, in the second century AD. The original structure was 34 meters, or about 112 feet. In the late 18th century it was renovated extensively, and another 21 meters (69 ft.) was added to its height. Today the tower is designated as a UNESCO World Heritage site. The tower is tied to Geryon, a giant in Greco-Roman mythology.