The Bock Casemates in Luxembourg city is celebrating its 20th anniversary of its first listing on the World Heritage List of UNESCO; on Saturday 1 March it reopened its doors for the 2014 tourist season.

The Bock Casemates and Pétrusse Casemates are the longest in the world and the No.1 tourist attraction in Luxembourg, with over 100,000 visitors annually. The labyrinthine underground galleries hewn in the rock are unique and reflect the glorious past of the legendary fortress city.

Classified since 1994, the Casemates have been thoroughly cleaned during the winter.

For four centuries, Luxembourg was under foreign rule, and the best engineers of the new masters (Burgundians, Spanish, French, Austrian, German) transformed the city into a fortress that became known as the "Gibraltar of the North". The defense of the citadel was provided by three fortified belts with 24 forts and 16 other powerful works and an extraordinary underground network of bunkers stretching for 23 km, spanning several floors and up to 40 meters deep.

The first casemates were built in the Pétrusse in 1644, under the sovereignty of Spaniards who modernised the medieval fortifications. Then, in the early 18th century, the Austrians perfected the defensive system of the Pétrusse Valley. The Bock Casemates, dug by the Austrians in 1745-46, were spread over an area of ​​1,500 m2, and could accommodate a garrison of 1,500 soldiers with their equipment including fifty guns. After the dismantling of the fortress in 1867, the casemates were partly destroyed and reduced to 17 km in length.

Today, the Bock Casemates are accessible to the public, with or without guided tours. The Petrusse Casemates will be open a little later on, during the Luxembourg school holidays at Easter.

Casemates du Bock: Open: 1 March - 31 October 2014 daily from 10:00 to 17:00; Admission: adults €3 (groups min. 10 pers. €2.80), children €2.50.

Pétrusse Casemates: Open during holidays and school holidays in Luxembourg, specifically from 21 June to 15 September 2014 with trilingual tours (DE, FR, EN); Open daily from 11:00 to 16:00; Admission: adults €3 (groups min. 10 pers. €2.80 per person), children €2.50.

Photo of Bock Casemates by Cathy Giorgetti