Question:

Which planet(s) did Aliens come from?

--question from Netherlands

Answer:

Aliens are popularly attributed with coming from many different places, including inside the Earth's crust, other planets in our solar system, other galaxies in the universe, other dimensions, and even from the past or future.

Though some of the above possibilities are more likely than the others, we are unable to state their origin. If nothing else, it is likely that Alien groups visiting Earth would be coming from different places in the universe, rather than just one.