The footage reveals that Apple has started installing the massive glass window panels on the exterior of the main ring structure. We also get a good look at the underground auditorium which will likely serve as Apple's venue for future keynotes and product unveilings. It will seat about 1,000 people.
Apple is planning to finish construction on the new campus by the end of the year. Check out some past videos here and please follow iClarified on Twitter, Facebook, Google+, or RSS for more construction updates.