Grand Californian Hotel: In the main lobby, on the left side of the fireplace, there are three round stones (amongst the rectangular ones) that seemingly create a Classic Mickey.
However, we're not quite sure about this Hidden Mickey, as viewing it is a little tricky. It can only be seen clearly from the right side of the fireplace, facing straight on or looking from the left of the lobby, the Mickey isn't quite visible. By the way, we have also wondered if Imagineers designed this Hidden Mickey to be some sort of optical illusion. In order to get our shot, we took our photos from just to the right of centered (if facing the fireplace), from the third floor balcony.