Bock Casemates

The Bock Casemates are a series of subterranean tunnels and passageways, the first of which were built in 1644, under the Spanish, later being expanded by the French and the Austrians.

Delving down to a depth of up to 131 feet underground and spanning 14 miles at their peak, the Bock Casemates were part of Luxembourg’s famed defences.

Bock Casemates history

The fortress’ casemates, the fortified gun emplacements, were started by the Spanish in 1644, using the cellars of the medieval castle as their basis. Extended by the noted French fortification engineer Vauban in the 1680s and fully realized by the Austrians in the mid-18th century, the Bock Casemates became much more than cannon perches.

It was in 1744, the passages that remain today were created. The site had 23 kilometres of tunnels delving as deep as 40 metres below the fortress. This included not only 25 artillery slots, but also stables, storehouses, workshops, kitchens, bakeries, slaughterhouses, and barracks for 1200 soldiers. The central passage is 100 metres long and seven metres wide and a 47 metre deep well supplied the installation with fresh water. The casemates helped the Bock resist a seven month siege by the French Republican Army in 1794. When the Habsburg forces in the fortress eventually surrendered, the walls remained unbreached.

Ultimately, the Bock proved too valuable, and its destruction (as well as the perpetual neutrality of Luxembourg) was ordered by the 1867 Treaty of London in an effort to defuse tensions between France and Germany. The demolition took 16 years to complete. However, the casemates could not be destroyed without also destroying part of the city, so 17 kilometres of the subterranean tunnels still remain.

Mostly closed down in the 19th century, the Bock Casemates were opened to the public in 1933. They then reprised their protective role in a different format during World War Two when they provided shelter for 35,000 people.

Bock Casemates today

Today, the Bock Casemates are open to visitors, who can wander through all the open tunnel passages, an extensive network of main thoroughfares and small, dead-end offshoots. The casemates were dug out on different levels, with some as far as 40 metres below the surface. About 17 kilometres worth of winding, dirt-floored passages and stairs are open to the public.

They also form part of the World Heritage site of the City of Luxembourg. Visitors today can still descend from the heights of the Bock to explore the expansive military engineering marvel below. The ruins of the fortress above offer a 360-degree view of the city

Getting to Bock Casemates

The hills leading up to the fortress ruins and casemates entrance are steep. Visitors can park at the bottom of the hill and enjoy the views of the city whilst making their way up to the site.