The Tate Modern is undergoing something of a facelift over the next few years, specifically erecting the weirdest construction in all of Christendom smack bang in front of it.
This hasn't deterred work on the existing building, however. Recently, a number of skilled workers have been shipped in every day to work on replacing the panels surrounding the very top of its impressive chimney (Wikipedia tells me this bit is called a "Swiss Light", apparently). Such an important and historic structure needs special care and attention, and only the best technology the human mind can create.
But to save some cash, they just lashed a bunch of ladders to the side.

Just goes to prove that there are indeed some people who have no natural fear of heights, especially if you take into account that before starting to climb they're already on the roof of a five-storey building.

I'd quite like to see Fathers for Justice have a go at getting up there.