Anyone living in London will have noticed that in preparation for the Olympic Games, a myriad of shiny new buildings, facades and artworks are materializing all over our City. This weekend I decided to bypass the luster and ostentation of new sights, and the glister of resurfaced old ones. I took a closer look at the things that have de-materialised, or are simply not there. (Like the Australian team bus that got lost somewhere between Heathrow and the Olympic Park last week, being spotted briefly somewhere around Buckingham Palace.)

I took a look at some invisible visions and the Hayward Gallery's exhibition Invisible Art of the Unseen...