The Cabinet War Rooms in London, where Churchill ran the war.

I bought this poster at the War Rooms in London. Mine is mounted in the bathroom. Please don't let Pat Harrison find out.

Been there, seen that. It's where I learned that Churchill awoke to a champagne breakfast, even in wartime.

Now that's impressive.

The Churchill War Rooms, by Luke J. Spencer (Atlas Obscura)

Hidden deep underneath the streets of Westminster lies what was once one of the most secretive and protected parts of London. As the German Luftwaffe pulverized Britain during the Blitz, a system of bunkers and tunnels protected the British government, as Sir Winston Churchill and his chiefs of staff desperately plotted to secure Britain’s defense against the impending Nazi invasion.

The Churchill War Rooms remain remarkably preserved. After the last V2 rocket hit London, and victory in Europe was secured, the government returned to its daily duties above ground in the Houses of Parliament and the War Rooms were simply sealed up and forgotten. They remained so until 1984, when custody was handed over to the Imperial War Museum and the bunkers were opened to the public. Today the hidden complex looks just as it did in 1945, as though Winston Churchill had just left the room and was about to return.