Auguste Piccard went up 10 miles (16 km) height in a balloon capsule in 1931. What did he see?

This was in 1931, before NASA.

"The story of their adventure surpasses fiction. During the ascent, the aluminum ball began to leak. They plugged it desperately with vaseline and cotton waste, stopping the leak. In the first half hour, the balloon shot upward nine miles. Through portholes, the observers saw the earth through copper-colored, then bluish, haze.

It seemed a flat disk with upturned edge. At the ten mile level the sky appeared a deep, dark blue. With observations complete, the observers tried to descend, but couldn't. While their oxygen tanks emptied, they floated aimlessly over Germany, Austria, and Italy. Cool evening air contracted the balloon's gas and brought them down on a glacier near Ober-Gurgl, Austria, with one hour's supply of oxygen to spare".

Popular Science, August 1931 p. 23.

The name of this short documentary film is "Professor Piccard and his Flat Earth Discovery".