It was year 3000 when robots took over the world. The remaining survivors remained in a bunker no one (even them sometimes) could get in. They quickly made a plan and it ended up working but before the leader of robots was destroyed he put a curse on the world.

One year later aliens took over the  world. they had even better technology than robots, but they HATED loud noises so if you made any sound at all they could track you down and take you to space without any equipment so you wouldn't be able to breathe.

A sneeze equals death. You can no longer speak or use anything that makes noises, what do you do? Some people would stitch their mouths shut but you would die of hunger, seems death either way doesn't it? But what would you do?

Billions of people die the first day. At the end of the day there is only 1 billion people left alive. They all try to stay up incase they snore while asleep but some were very tired. The next morning only 978 million people are left on Earth.