Les casemates de la Pétrusse

Casemates of the Pétrusse - Petrusskasematten

Useful Information

Location: Place de la Constitution Luxembourg, 2450, Luxembourg.
(49.6094287, 6.1299324)
Open: All year Mon-Sat 11:30, 12:30, 14, 15, Sun, Hol 11:30, 12:30, 13:30, 14:30.
Fee: Adults EUR 15, Children (4-12) EUR 7.50, Children (0-3) free, Students EUR 12, Seniors EUR 12.
Classification: SubterraneaCasemates
Light: LightLED Lighting LightColoured Light
Dimension: L=17 km.
Guided tours: D=45 min, L=450 m, St=242, Max=15.
Photography: allowed
Bibliography: LCTO (2022): Die Petruss-Kasematten: Wo Felsen zum Leben erwachen, ONS STAD, 126, pp 8-10. pdf
Address: Les casemates de la Pétrusse, Place de la Constitution/Boulevard F.D. Roosevelt, 2450 Luxembourg.
Luxembourg City Tourist Office, 30, Place Guillaume II, 1648 Luxembourg, Tel: +352-222809, Fax: +352-461046. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1644 the Spanish modernized the Medieval fortifications and built large bastions, including as the Beck Bastion with the casemates de la Pétrusse.
1673/74 the Spanish add the Ravelin Beck-Jost in the shape of a half-moon.
1684-1697 walls raised by Vauban.
1728-1729 Austrian staircase built, which connected the casemats underground with the other side of the valley.
1746-1751 casemates de la Pétrusse in their current form, referred to as the battery de la Pétrusse, built by the Austrians.
1860 further strenghtened.
1867 partly dismantled due to the First Treaty of London.
1871 the Société de tir à l'arquebuse (arquebus shooting society) had its shooting range in the casemates.
1886 The Compagnie des Grands Vins de Champagne E. Mercier, founded in 1858, started production near the railway station and used the casemates to store their bottles.
1890s the gardeners Backes and Schneider grow mushrooms in the "Pastèitchen".
22-JUL-1933 opened to the public.
1994 inscribed on the UNESCO World Heritage List.
2015 closed for renovation.
05-JUN-2022 reopened after the works of mise en conformity and mise en valeur.


The casemates de la Pétrusse or Péitruss-Kasematten (Casemates of Saint Peter) were first created by the Spanish who modernized the Medieval fortifications in 1644. They built several bastions, including the Beck bastion, whose platform is today called Place de la Constitution. The architect was Isaac von Traybach. In 1673, the Spanish reinforce the Beck bastion with the semicircular Ravelin Beck-Jost. The locals called it Ravelin du Pâté or Pastèitchen (muffin), in their typical disrespectful way, which allowed them to survive centuries of occupation. This fortification is largely preserved until today.

The casemates got their final form by Sébastien Le Prestre de Vauban during the French occupation. In the years between 1684 and 1697 he raised the walls of the Beck Bastion to their present level. The underground galleries were 23 km long at the end. The fortified city of Luxembourg was called the Gibraltar of the North.

In 1714 Luxembourg fell under Austrian rule with the Treaty of Rastatt. They erected the Fort Bourbon on the other side of the Péitrussdal from 1728 to 1729 under the leadership of the fortress engineer Simon de Beauffe. The idea was to dam the river in case of an attack and so make the valley impassable. To connect this fort with the city, a staircase, the so-called Austrian staircase was built, which connected the casemats underground with the other side of the valley. It was an underground connection between the inner and outer fortifications. Between 1746 and 1751, the Austrians also built the casemates de la Pétrusse in their current form, which were referred to as the battery de la Pétrusse.

In 1860, it was strengthened further, just to be partly dismantled seven years later. The Luxembourg Crisis was a diplomatic dispute and confrontation in 1867 between France and Prussia over the political status of Luxembourg. The confrontation almost caused war, but was peacefully resolved by the First Treaty of London. As a result, Luxembourg, which had been occupied for centuries, became a sort of neutral buffer between the empires. But this required that it was demilitarized. Huge parts of the casemates were destroyed, the length was reduced to 17 km. But they extended below the city center, it was impossible to destroy them without damaging a large part of the city.

The remain were used later for various purposes, to grow mushrooms, to store champagne, to install an underground shooting range. At the beginning of the 20st century it was used for various functions, concerts and events.

The tunnels were of great importance during the two world wars. They served as an air raid shelter with the capacity to protect 35,000 people in the event of a bombardment. Between the wars, in 1933, this case mate and the one on the Bock were both opened to the public. Since 1994 the casemates, the bastions as well as the old town are inscribed on the UNESCO list of World Heritage Sites.

The casemates were shown on guided tours in a rather raw state, there was only basic incandescend light installed. There was water seeping in, creating huge puddle on the floor and staircases. The operator, the Luxembourg City Tourist Office (LCTO), used wooden planks to keep the visitors shoes dry, but those started to rot. Due to the safety issues, LCTO and City decided in 2015 to close the casemates for renovation. It seems there were numerous problems, or probably only the money problem, and nothing happened until finally in 2019 the renovation actually started. The completion was planned for 2018, but the casemates did not reopen until 2022.

The responsible claim that they decided to "highlight the casemates with a scenography". We have no idea what a "scenography" is, but we guess they talk about coloured light and strange art-like installations. The Austrian Staircase was also renovated, nevertheless it is not part of the tour, it is the access to an additional emergency exit. The exit of the tour is down below in the Petrus valley, visitors can return to the city through a series of staircases or make a walk through the nice valle, which is more or less a park.