Head of Apple Retail Ron Johnson gave some insight into the planning behind the Boylston Street location. The spot was picked out in 2000, but took eight years of planning to get it built. Because of Apple's recent success, the store has grown significantly from what was originally planned. If the store were built back in 2000, when the retail initiative was just getting started, it would have been one floor. If it were built in 2005, when the iPod was just taking off, it would have been two floors. Now, with the success of the iPhone, iPod and Mac lines, the store has three floors.

The first floor is all Mac, the company's "most important product" according to Johnson. Floor two is dedicated to iPod, iPhone and all the third party accessories Apple offers. The third floor is dedicated to service, with a massive Genius Bar, sections for one-on-one, workshops and a second location for Apple's new "Pro Labs" initiative.

The Genius Bar, which boasts 17 black stools, can serve 1,000 people per day at full capacity, with the store open from 8AM to 11PM.

The store is also environmentally friendly, with vegetation on the roof and a rainwater recollection system which directs water from the roof directly into the Back Bay water table.

The store opens tomorrow, Thursday the 15th, at 6PM.(Roof photo by Joyce Hannon. All others by Jordan Golson)

Sorry, I'm not so sure this is even close to the biggest. I am stupid. Some other sites have questioned this claim. Apple has never been forthcoming with information on upcoming stores, so we have to work this one out on our own.

The Boston Globe claimed back in 2007 that the store would be 21,350 square feet. The current largest location, the Regent Street store in London, has somewhere around 28,000 square feet of space.

ifoAppleStore says "...the [Boylston Street] lot is only 6,384 square-feet, so the store would have to be at least five stories to be larger than Regent Street (London), at 28,000 s.f."

The store is at least four stories above ground, (if you include the half-length fourth story that is hidden from street view) and likely has a floor or two of basement for stock-keeping purposes. This easily puts the store in the 26-32,000 sq ft range needed to beat Regent Street. There also may be discrepancies here between "sales space" and "back-of-house" space and what the employee meant by "largest in the world."

Apple hasn't gotten back to repeated requests for confirmation. Tag this one "plausible."