This article from The Atlantic about the history of London's private parks opening to the public during WWII is fascinating.

In the early 1940s, in the name of the war effort, the British government ordered citizens to tear down the tall, black railings that surrounded London's many private gardens. Cast iron barriers were cut from all the city's exclusive parks, supposedly bound for munitions factories and then, in another form, to the Continent. George Orwell hailed the removal as a "democratic gesture."

Formerly private gardens like Russell Square spent several years during the war open to everybody. At the close of the war, as property owners tried to put the railings back up, Orwell and others defended the newly public spaces of the city. Those who had owned the city's parks prior to the war accused the writer of advocating thievery.

The art project that commemorates it is interesting too–a sound effect that simulates running a stick over the bars as you walk by. It sounds better than it looks in practice, but I really like it. A fascinating history of parks.