The two you must do
1. The Wenzel Circular Walk. Roughly 5 km and two hours, starting at the Bock and looping through Pfaffenthal, along the Alzette, up through Grund and back to Ville Haute. Numbered panels explain 1,000 years of fortifications. 2. The Corniche and Grund descent — shorter (about 45 minutes), starting at Plateau du Saint-Esprit, along the Corniche, then down the Montée du Grund into the valley for a drink at Scott's or Konrad Café before climbing back up.
The Wenzel is the single best walk in the country if you want to understand why the city looks the way it does. It's well-signposted with a free downloadable map from the tourist office on Place Guillaume II. Do it in the morning before the ramparts get hot in summer. The Corniche-Grund descent is what to do if you have half a day, not a full one — it hits the two showcase views and puts you at valley level for lunch.
Three more for a second visit
3. The Pétrusse Valley walk, through the reopened park below the Adolphe Bridge — recently redesigned with restored 18th-century casemate walls and quiet paths along the stream. 4. Pfaffenthal to Clausen along the Alzette, a flat 30-minute stroll past old mills and the Mansfeld gardens. 5. Kirchberg architectural walk, from the Philharmonie past the European Court of Justice and along the Avenue J.F. Kennedy — modernist and contemporary buildings on a scale you don’t get in the old town.
The Pétrusse walk is the sleeper — most tourists never descend into it, and it's the best introduction to how the valleys structured the city's defences. The Alzette valley walk is what to do with kids or grandparents; genuinely flat, shaded, and pretty. Kirchberg is only interesting if you like modern architecture — it's a business district, not a neighbourhood, and evenings are dead. Skip it otherwise and spend that hour back on the Corniche.
Good to know
Are these walks doable in winter?+
Yes, but the Wenzel has some steep stone stairs that get slippery when wet. Grip soles and daylight hours are what to plan around.
Can I do the Wenzel with a stroller?+
Not comfortably — there are staircases in both directions. The Alzette valley walk (Pfaffenthal-Clausen) is the stroller-friendly option.