There was a patch of forest that swallowed the snow. Everything around it was white - powdery hills, peaks indistinguishable from the clouds, wide frozen fields - but this patch of forest was dark. The snow just couldn't settle. I don't know where it went, but from 30,000 feet above it looked like a cave, a hole in the earth with no explanation.
On a different flight, only a week later, on an entirely different landmass, I saw straight lines that must have been roads, but my sense of proportion had warped. I couldn't tell if the land was flat, or if those lines went straight up in the air, bound to the rising flank of a mountain range.