airfield recognition
I was doing my PPL in Florida, and doing my dual X-country night flight. At some point in time we were supposed to be overhead a certain airfield. "Okay, let's check" said the instructor. So she tuned in the frequency for the Pilot Controlled Lighting, clicked a few times and sure enough, the airfield lit up underneath us.
Not the most "green" way of navigating, but it was fun nevertheless.