The Aliens did this because
it was their way of cleaning up the planet and bringing down the number of people living on Earth (to possible extinction).
shareWho says they were ALIENS?
- Perhaps they were ANGELS?
- Perhaps they were machines invented by MANKIND
- Perhaps they were an Earth spawned race that came back to see their planet inhabited by squatters.
- Perhaps it was a big mistake and the wrong planet was targeted.
- Perhaps there are SQUARE ships and TRIANGLE ships over different cities that make people stand in SQUARES and TRIANGLES ... ?
They were aliens.
Schrodinger's cat walks into a bar, and / or doesn't.