The Tower of Hercules is an ancient Roman lighthouse, located on a peninsula approximately 1½ from the center of the city of A Coruña. The tower remains a sentinel from days long past. It is known to have existed by the 2nd century, built or perhaps rebuilt under Trajan, perhaps on foundations and just possibly following a design that was Phoenician in origin. At its base is preserved the cornerstone with the inscription MARTI AUG.SACR C.SEVIVS LUPUS ARCHTECTUS AEMINIENSIS LVSITANVS.EX.VO, permitting the original lighthouse tower to be ascribed to the architect Gaius Sevius Lupus, from Aeminia (an ancient Roman town near present-day Coimbra, Portugal) in the former province of Lusitania, as an ex voto dedicated to Mars. The tower has been in constant use since the 2nd century. Originally it was constructed with an ascending ramp encircling its sides, for oxen to bring cartloads of wood to keep the light fueled at night.
According to Gaelic legend embodied in the 11th-century compilation Lebor Gabala Erren— the "Book of Invasions"— King Breogán, the founding father of the Galician Celtic nation, constructed here a massive tower of such a grand height that his sons could see a distant green shore from its top. The glimpse of that distant green land lured them to sail north to Ireland. A colossal statue of Breogán has been erected near the Tower.