The Bock is a promontory in the north-eastern corner of Luxembourg City's old historical district. Offering a natural fortification, its rocky cliffs tower above the River Alzette, which surrounds it on three sides. It was here that Count Siegfried built his Castle of Lucilinburhuc in 963, providing a basis for the development of the town that became Luxembourg. Over the centuries, the Bock and the surrounding defenses were reinforced, attacked, and rebuilt time and time again as the armies of the Burgundians, Habsburgs, Spaniards, Prussians, and French vied for victory over one of Europe's most strategic strongholds, the Fortress of Luxembourg. Warring did not stop until the Treaty of London was signed in 1867, calling for the demolition of the fortifications. Ruins of the old castle and the vast underground system of passages and galleries known as the casemates continue to be a major tourist attraction.

Luxembourg, also known as Luxembourg City, is the capital city of Luxembourg and the country's most populous commune. Standing at the confluence of the Alzette and Pétrusse rivers in southern Luxembourg, the city lies at the heart of Western Europe, situated 213 km (132 mi) by road from Brussels, 372 km (231 mi) from Paris, and 209 km (130 mi) from Cologne. The city contains Luxembourg Castle, established by the Franks in the Early Middle Ages, around which a settlement developed.