>watching interesting things like cities.

Not only cities, watching natural formations like lakes, rivers, fields, forests, hills and mountains from above is a unique perspective (compared to seeing the same from land), and very cool too. I remember being glued to the window, for tens of minutes (at least), on a flight from Europe to the US, when passing over the Arctic (or near it, not sure, but northern seas anyway), seeing vast expanses of ice floes and blue-green water glittering in the sunshine from high above. Then passing over Goose Bay as we crossed over Canada into the US, that was great too. Miles of green meadows or grassland.