The interesting thing is during the northern fall and spring, less so in winter on the ORD-HKG nonstop, it starts to get dark within 2 hours of departure, and just when you think it will be dark for the rest of the way, the sun seems to hang very low on or just below the horizon for a good portion of the flight just off the left side of the plane. This then changes as you start swinging southward over Siberia and the sun seems to rise in the west (on the right side of the plane now) until it starts setting right around the time you descend into HKG.
Quite a spectacular view. The return flight is less so, though because it basically follows a Pacific route over the northern part of the Pacific Ocean at or just south of Alaska to ride the jetstream.
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