In 1954, US Air Force physician John Paul Stapp strapped himself to a rocket-powered sled. Launched at over 1,000 km/h, he was brought to a halt in just over a second, enduring about 46 g. He came out with bloodshot eyes but alive, and his tests helped push forward the adoption of seat belts.
Cooled below −183 °C, oxygen turns into a pale blue liquid. Pour it between the poles of a strong magnet and, instead of flowing away, it hangs suspended between them. The reason lies in its unpaired electrons, which respond to the magnetic field. Liquid nitrogen, by contrast, is colourless and pours straight through.
In 2012, Felix Baumgartner jumped from a capsule hanging beneath a balloon, about 39 kilometres up. In that extremely thin air almost nothing slowed him down, and he reached around 1,358 km/h in free fall, or Mach 1.25. He became the first person to exceed the speed of sound with nothing but his own body.