In the Timeless Universe
When Catholicism was outlawed in the region during the 1500s a network of secret tunnels known as Priest Holes where built in Castle Varlar to help sneak priests on and off the ground.
During World War II the Nazi High Command took over the castle and built a rocket launch pad on the grounds of the castle. In December 1944 the high command planned a celebration at the castle to commemorate the launching of a V2 rocket that was planned to strike a civilian target in Belgium. Ian Fleming Used his cover at the not the officer to Infiltrate the party, smuggling Lucy Preston in as his secretary, in hopes of capturing Wernher von Braun and delivering him to the Allies. During the party, Lucy met up with Garcia Flynn where he explains his plan to turn von Braun over to the Soviet Union before tipping off the Nazis of Fleming's and her presence. During the mission Wyatt Logan and Rufus Carlin broke onto the launch pad grounds and sabotaged the V2 rocket then later infiltrate the castle in order to save Lucy. The team finally met up and barricade themselves in a study where Lucy used the hidden Priest Hole in the fireplace to help escape into the forest.
After the war was over Fleming used Castle Varlar as a source of inspiration for his work as an author with the castle serving as the model for the main setting in the novel Weapon of Choice and having the Priest Hole serve as a component in the Bond movie Skyfall.