Cruising: At Sea
Pardon the obvious observation, but being at sea means being in the middle of nowhere. Look in every direction and there's nothing on the horizon in any direction. It's a first for me. As a city-dweller, the idea of being surrounded by essentially nothingness is fascinating. Particularly, it makes me think about sailors through history surrounded by a blue void for days or weeks or months at a time.
There's a weird cognitive dissonance being so isolated from the rest of the world, yet still surrounded by a thousand people.