most culture is about walls and boundaries. Think about it. No walls, no culture.
It was an architect who tipped me on this but it is almost a truism and in plain sight.
Art? Painting? On a wall. Oh, a statue you say? In the garden. (= walled off piece of land). Want a drink? Cup is a walled off space. Etc ad libitum.
I seem to remember it was in precisely 2010 that Merkel got awarded the Kalergi Prize.
The Kalergi plan is still in full effect through the Declaration of Barcelona (1975?) and today (a few weeks back) the Declaration of Marrakesh (as part of the so called Process of Rabat) which has been signed by dignitaries from all over Europe (except maybe a few of the Visegrad countries). pdf related