A 5-kilometre signposted heritage walk that links 1,000 years of city building in a continuous loop. From Place Guillaume it drops into the Pétrusse, climbs to the Bock, threads through the casemates, and returns via the Alzette valley. Free, self-guided, with information panels at each stop.
Allow three hours at a brisk pace, half a day if you stop for sights and a long lunch in the Grund. The best single way to grasp the layered geography of the city.