@psychographer effectively it's not very easy: it's an artwork hanging in the stairway of a museum in Lisbon. Its title is "Google airplane" and it is a real little aircraft whose lower side is covered with photos of a cloudy sky while the upper part is covered with photos of the ground (I assume, printed from google maps)
@ltodd thanks, Lyn! Much appreciated!
@joysabin too nice of you! Thank you a lot, not only for the fav!