Saint-Leu-d'Esserent is a town in northern France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 situated on the banks of the river Oise

Oise River

The River Oise is a right tributary of the River Seine, flowing for 302 km in Belgium and France. Its source is in the Belgian province Hainaut, south of the town Chimay. It crosses the border with France after about 20 km. It flows into the Seine in Conflans-Sainte-Honorine, near Paris...

. It is designated municipally as a commune

Communes of France

The commune is the lowest level of administrative division in the French Republic. French communes are roughly equivalent to incorporated municipalities or villages in the United States or Gemeinden in Germany...

 within the département of Oise

Oise

Oise is a department in the north of France. It is named after the river Oise.-History:Oise is one of the original 83 departments created during the French Revolution on March 4, 1790...

. "Saint Leu" is notable for 3000 square metres (32,291.7 sq ft) of mushroom caves under the Thiverny

Thiverny

Thiverny is a village in northern France. It is designated municipally as a commune within the département of Oise....

 plateau.

History

During World War II, the caves were one of three major underground V-1 flying bomb

V-1 flying bomb

The V-1 flying bomb, also known as the Buzz Bomb or Doodlebug, was an early pulse-jet-powered predecessor of the cruise missile....

 storage depots. In addition to the caves, the facility included blockhouse

Blockhouse

In military science, a blockhouse is a small, isolated fort in the form of a single building. It serves as a defensive strong point against any enemy that does not possess siege equipment or, in modern times, artillery...

s, bunkers, flak

88 mm gun

The 88 mm gun was a German anti-aircraft and anti-tank artillery gun from World War II. It was widely used by Germany throughout the war, and was one of the most recognizable German weapons of the war...

 emplacements and railway links. Allied intelligence firmly identified late in June 1944 that Saint-Leu-d'Esserent and Nucourt

Nucourt

Nucourt is one of the communes of the Val-d'Oise department in the Île-de-France region of northern France and the location of limestone caves which were used as a World War II V-1 flying bomb storage depot.-References:** -External links:* *...

 were V-1 storage depots. On 27 June 1944, Saint-Leu-d'Esserent was initially bombed by the US Army Air Force, then on July 4/5 1944 by two RAF forces (the first unsuccessfully used Tallboy bomb

Tallboy bomb

The Tallboy or Bomb, Medium Capacity, 12,000 lb, was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis and deployed by the RAF in 1944...

s in an attempt to collapse the limestone roof of the caves). Finally on 7 July 1944, an evening RAF raid successfully blocked the tunnels.

The "storage dump at Thiverny" was bombed in 1944 on May 5,
July 11,
July 12,
and July 19.