20:50

This is one of the most extraordinary things I've seen in a long time. It's by Richard Wilson in the basement of the Saatchi Gallery. It takes a while to get your head around precisely what you're looking at. And what you're looking at is a room half filled with sump oil, which creates a surface so smooth and reflective that you see the ceiling. The oil's too thick and black to see through it. It's as though there's a mirror suspended in the room; the only way you know it's oil is because you can smell it and because of the metal walk way over on the left.