Lugo has a Roman wall, and unlike most Roman walls it has not turned into a fragment or a footnote. It runs around the entire old town, over two kilometres of it, built in the third century with dozens of towers, and it is still intact enough that you can walk the whole circuit on top. UNESCO listed it in 2000, saying it is the only completely preserved Roman defensive circuit in the world, and when you step up onto the walkway you can see why.
The walk takes about an hour at leisure, and it is the best way to get the feel of the place: you look down into courtyards, over rooftops and across to the cathedral, and the wall's several gates let you slip back into the lanes. The cathedral itself mixes Romanesque and later styles, and has the unusual privilege of keeping the host exposed on its altar. Beyond the wall, the Miño river runs close to the town, with green walking paths.
For riders, Lugo is a good base for the quiet interior of Galicia. The roads here wind over hills and through valleys with oak and chestnut, pasture and small stone villages, and traffic is light compared with the coast. The Camino Primitivo, the oldest pilgrim route to Santiago, passes through the city, so you will often see walkers on the road shoulders; give them room. The weather is wet more often than not, so keep an eye on the surface in the shade of the trees.
Lugo has nearly a hundred thousand people, with all the fuel and food you need. It is known for good meat and for pulpo, octopus boiled and served with paprika, and for the custom of bars giving a free small plate with each drink, which can make dinner an informal crawl. Park outside the walls, and walk in through one of the gates.