The Tube started it with art and poetry... and now it has spread to the DLR. At Greenwich Cutty Sark I noticed a poster advertising the art first (I'd arrived on the opposite platform).
We're about to go to the RMG 'Visions of the Universe' exhibition (as soon as I book tickets)... and we went to the Cutty Sark on our honeymoon so this one seemed very appropriate.