In the hall of the mountain king: Olafur Eliasson's Serpentine Pavilion.

Not only is the 2007 Serpentine pavilion not as awkward as I'd feared from the early publicity images - on the contrary, it is the best of these annual summer temporary structures since Toyo Ito and Cecil Balmond's back in 2002. It is also the tallest.

Icelandic artist Olafur Eliasson, and architect Kjetil Thorsen, have made an object which contrives to combine the cave and the mountain, interior and exterior. From a distance it looks as if it is made of patinated bronze or oxidised steel: closer inspection reveals that it is clad in precisely-cut dark-stained geometric plywood panels on a concealed steel armature.