You can have no idea what this is - I defy you to guess.
It's an old friend of mine and I used to visit it every year for a while. Then I got ill and things kind of fell in on me.
Actually, you really can't have any idea because what is light is dark and what is dark is light; it's an amazing work of art in the basement of the Saatchi gallery just off The King's Road in Chelsea.
What you are looking at is called '20:50' by Richard Wilson who has lined the basement with steel to about waist height then filled the tank with used sump oil.
This week I got to see it again.
It's a deep, deep black and at the same time it's highly reflective so that the top half of the room is echoed back at you in a very confusing way.
When I was there it was leaking a bit which was a problem - there is walkway which goes straight into the middle of the room and normally you can walk into the middle of the lake of oil so that you are completely surrounded by it.
Now that is a really weird experience.
When you first go in your eyes are besieged by the look of it all, your brain struggles to understand what you are seeing.
As you get used to it your nose takes over and you enjoy the smell of the oil - then just when you get used to the attractive smell of the volatile oils you realise that it isn't a nice smell at all.
Used sump oil is really quite carcinogenic - if you come into contact with it.
It's completely still and silent and at the same time it's a constantly changing relationship and very, very strange.
Like finding yourself on a completely alien planet or in the middle of a surreal dream.
(a don't stop till you drop production)
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