The vast Bock Casemates tunnel network encompasses a dungeon, prison and the Archaeological Crypt, considered the city’s birthplace. Along ramparts above, the Chemin de la Corniche promenade offers dramatic viewpoints.
Area: 51.47 km²
Population: 114,303 (Jun 2017) STATEC
Highest elevation: 402 m (1,319 ft)
Lowest elevation: 230 m (750 ft)