1. Launch a balloon with your own camera attached to it:
https://www.youtube.com/watch?v=UAifzh7_-cg
2. Sail around the world on your own.
3. Become an astronaut.
https://www.youtube.com/watch?v=UAifzh7_-cg
2. Sail around the world on your own.
3. Become an astronaut.
...but the curve is going the wrong way in that video!
The options were flat or spherical, now you've gone and complicated things by offering evidence for a concave earth.