The new £215m extension to Tate Modern, designed by Herzog & de Meuron, is gradually rising. With annual visitor numbers of around five million, the huge, brick-built former power station that has housed the UK's modern and contemporary art collection for the past 14 years could do with some more space.
I've always enjoyed museums at their quietest, just before closing perhaps, when you can get a painting, or a room even, to yourself. Whether this will be possible when the extension opens in 2016 we'll have to see. Much more likely is that, like road widening, the congestion will remain but with yet more traffic. The great news, on the other hand, is that so many people want to visit a museum of contemporary art.