“We originally wanted the hill to totally cover the arch,” says Winy Maas, founding partner of MVRDV, the Dutch architecture firm behind the pop-up hillock. “That was an interesting discussion, let me put it that way.”
I'll bet it was an interesting discussion. Hopefully it went along the lines of
"What if we cover Marble Arch with a big ugly mound?"
"No."
If the discussion went any further than that, fire somebody.