Roman Walls of Lugo

Around AD 270, as the empire's frontiers grew anxious, the Romans encircled the Galician town of Lucus Augusti with a rampart of slate and granite over two kilometres long, up to 15 metres high, punctuated by 71 towers. It is the only Roman city wall on earth to survive its entire circuit unbroken. For 1,700 years the people of Lugo have lived inside it, and today a continuous walkway runs the full loop along the top, past medieval gates cut through Roman stone. The wall has weathered Suevi, Visigoths and Napoleonic troops, an unbroken stone ring that quietly outlasted the empire that raised it.