Fulcrum, consists of five enormous, 55ft steel slabs apparently leaning against each other, though they are in fact welded together at the top to stop them falling over and incommoding passers-by. The idea is that art lovers can go inside, look up and watch the clouds scud overhead.
Unfortunately, Broadgate's health'n'safety crew seems to have doubts about the integrity of the welds, because they have installed their own counter-art installation Crowd Control Barriers to keep everyone out. Or perhaps the giant wigwam was being used as a refuge by smokers who, let's face it, have nowhere else to go these days.
Serra has made enormous sheets of steel his life's work. Google 'Richard Serra enormous pieces of steel' and select the 'images' option if you want to see what I mean.