Any evidence that aliens visited our planet?

As you know, we heard stories, documentaries, and movies about aliens. Are they real? From where they started. Is there any evidence about it? Well, there's a theory that life might have evolved on Earth, but was actually created on Mars. It has been proved that there was water found on Mars. But do aliens need water, i mean is it necessary to have water for life. You never know there might be other ways for having creatures, who might have different formations then what we have. What do you think about it?