This is the airport of Mérida, in the venezuelan Andes, early morning waiting my flight to Caracas. The airport is right in the middle of the city. The city itself is on plateau between two valleys, with very tall mountains on the sides (the highest just below 5,000 m - 15,000 ft). The picture is not tilted, it is the runaway (and the whole city, actually) that is inclined, to the point that people say that they are “going up” if they are going East, and “going down” if they are going West.
Despite the runway being quite short, there was a time in which the airport was served by jets, which could only be piloted by specially trained pilots. At that time the bakery in front of the airport had to close the doors every time an airplane was taking of, because of the noise of the fully powered jet engines, struggling to lift the craft from the ground before the end of the runway (this was happening just four times per day, fortunately).
Now the city is served by smaller propeller planes, that can do the acrobatic landing with more ease, and that are economic enough to fly several flights every day. If there are no clouds, of course, as planes still cannot land unless there is complete visibility (in fact, I took this photo while waiting for our plane, which was late because of the morning clouds hovering the city).