Fortification in Luxembourg City
The Bock Casemates are a UNESCO-listed network of underground tunnels and chambers carved into the rock cliff of the old city, originally built in 1644 and expanded over centuries. Entry is paid at a modest price. The tunnels stretch 17 kilometers and once sheltered 35,000 people during wartime. Budget travelers pay the cheap ticket and walk through the fortress tunnels with views out over the valley through cannon openings.
Nearby
Other places worth the walk, and what each one costs.
The Chemin de la Corniche is a pedestrian walkway along the edge of the old town cliff, called "the most beautiful balcony of Europe." Free. The path overlooks the Alzette River valley, the Grund district below, and the Bock Casemates across the gorge.
The Grund is the neighborhood in the valley below the old town, reached by a free public elevator from the Plateau du Saint-Esprit or by walking the zigzag path down. Free to walk.
Working out what Luxembourg City costs?
The whole of Luxembourg City