It's Day 42. Mention that to pretty much anyone here in London and they'll know what you mean. In two days time, illusionist David Blaine  will end his voluntary incarceration in a Plexiglas box suspended from a crane 40 feet above the River Thames.
Like his hero Houdini, Blaine decided London would be the ideal stage for his latest stunt. But when he entered the box, most Londoners didn't give a damn. What could be more boring than watching somebody not eat?
But over the last 42 days, we've learned a lot. For a start, we've learned how loutish people can be, lobbing eggs at Blaine's box, aiming laser pens at his eyes, cooking food below him and flying Big Mac-laden toy helicopters around his head.
But most of all, Blaine's experiment has reminded me of the power of mystery: the mystery of how (Have we been fooled by technical wizardy into believing he's in the transparent box, when really he's ordering room service in a Park Lane hotel suite?) and the mystery of why (Why would anyone in their right mind choose to spend 44 days in a box?).
Cloaked in mystery, Blaine-in-a-box has become London's biggest tourist attraction and inspired 42 days of debate among people who professed not to care in the slightest on Day 1.
In recent years, businesses have been urged to become more transparent, revealing warts and all to customers, auditors and law-makers. Against a backdrop of corporate shenanigans, that's not an unreasonable request, but we do business no favors by robbing it completely of the power of mystery.
In an interview  last month with Italian business magazine Economy Italia, Kevin Roberts , CEO of ad agency Saatchi & Saatchi , said this: "Advertising today carries too much informative content. In a world pervaded by information, the most interesting thing is what isn't known -- mystery."