Built sometime around the 3rd century, the ring of towers and walls which now surround the city of Lugo were originally constructed to protect a Roman city from barbarians, and they continue to contain the world's only city that is completely surrounded by ancient Roman walls.
The rocky ring surrounding the city of Lugo, which sits on the site of the ancient Roman city of Lucus, remarkably looks as though it could have been built only dozens of years ago instead of thousands. Making a bulbous circuit around the border of the town, the ancient walls stand almost 40 feet tall at their highest point, with curved lookout towers bulging out of the wall at irregular intervals. The top of the wall stays a consistent 14 or so feet in width which can still be walked in a complete circuit. Ten gates were built into the wall, and of them, five are still the Roman originals.
Though the walls were built to fend off the Germanic hordes, originally being joined by moats and interior defenses, those same hordes are now welcomed as tourists. Visitors are encouraged to stroll atop the wall from which they can see the entire town of Lugo and beyond.