Beneath the turbine hall of the former Bankside power station, the Tate Modern has developed a series of vast former oil tanks into an exhibition space, specifically for 'performance' art.
I have to say that most of these felt pretty trivial to me and unworthy of visiting; except one.
Outside, you will have to wait in a queue. It is the only queue in the Tanks. And depending upon the whims of the supervising staff, you may have to wait some time. The queue is part of the performance. Sometimes they make people wait more than an hour, or until they lose interest and disappear. Sometimes they do a deal - we were invited through from halfway down the queue by a woman who whispered in our ear that she would let us in for a piece of chewing gum...
Inside, what felt like an exclusive audience - probably no more than six people - wandered around shell shocked by the terrifying high-pitched noise of a metal grinder - sparks flying eight feet into the air - as a man sat nonchalantly polishing a massive metal sign.
On it, in that chillingly brutal and utilitarian, twentieth-century-industrial-foundry sort of way, were the words Arbeit Macht Frei..