One of the reporting points we use when flying around the Peninsula is SLAC, officially VPSLA, the Stanford Linear Accelerator. It's a 2 mile long straight line on the ground, very easy to see, and it's at a convenient distance from the San Carlos and Palo Alto airports for calling in to land.
And in case you're not sure when you're exactly overhead, you can always hear it chirping away on your radio.
I'm sure there's some rational explanation for why a high energy physics installation 2000 feet below me would cause my VHF radio to pick up random signals. But aviation is a faith-based enterprise, not science, so when I hear the creepy noise I just whisper "4 8 15 16 23 42" to myself to keep the plane from falling out of the sky.