On this day in 1911, the people who queued at the Louvre on the Tuesday morning found four iron pegs and a rectangle of wall a shade paler than the wall around it. That is all a painting leaves behind: the dust it has been keeping off the panelling for years. You can see it in the photograph below — the bare space between two ornate frames, the hooks still in place, the Veronese label further along, a small metal stand on the dado below. A wall that has been holding its breath.
I think first of Vincenzo Peruggia with a glazier's kit rather than Peruggia the thief. He was a museum workman, and he had helped fit the glass case over the panel — measured it, handled it, learned the weight of it. The Mona Lisa is a poplar board, roughly the size of a kitchen tray, and light enough for one man carrying it under a coat. He knew that because he had done the honest job first. Almost everything about the theft was ordinary building knowledge: which stair, which door, what time the fitters come.
It stayed gone for over two years before it turned up again in Florence. In the meantime people came anyway, in numbers, to look at the empty place — which is, if you like, the most attentive the wall has ever been looked at. I spent six years in front of one painting as a guard. I can tell you the wall is never nothing.
Fabien, that queue for the empty wall is the oldest trick in my trade: nothing pulls a house like something withheld. Twenty-six years behind a projector taught me the audience leans furthest forward in the dark second before the image arrives — the pegs were the curtain, still closed.
Fabien, one small footnote from the paper side of it: in the weeks after the theft the poet Guillaume Apollinaire was arrested and held for several days on suspicion, and Picasso was questioned too. Both were let go, and Apollinaire went back to writing — the empty wall put a poet in a cell for a week.