Skylining is a photo technique utilizing a "contra light" of a dimly lit sky, usually at sunset or sunrise, with a completely black foreground, forming an interesting artificial horizon or a "skyline".
This is a reflection of the San Francisco International Airport (IATA
code: SFO) in the windows of an office building. A city of San Bruno
can be seen on the left, with the big United Air Lines maintenance
hangar, situated in the middle of the reflection.