Something is common to the way all these photos have been shot. All these were posted online on a Google+ page between April to June 2012. So what's special to the way they've been taken?
[+ Show Answer]
These were all taken using Google's new set of head-mounted devices that embed computing within spectacles (the project's called Project Glass). These glasses will let wearers take photos, overlay maps on the field of vision etc.
More here.
Images: the Project Glass Google Plus page 