Surely the most amazing and humbling views to be seen by any human on a regular basis. The view from a U-2 cruising at 70,000ft as the sky above turns black and the curvature of the Earth is visible.
Despite first flying over 50 years ago, the U-2 continues to serve in the USAF, having outlasted its Mach 3 replacement, the SR-71 (also from Lockheed).

The only people to have gone gone higher on any sort of regular basis were SR-71 pilots.




Vid I found