Cropcircles? They are man-made for sure. It has been proven countless of times.

In fact, why o why would aliens use crop fields to communicate? It really doesn't make sense.

In fact, it doesn't make sense for navigational purposes either. Just think about it, if it's supposed to be a marking for a special place, why not just use a simpler shape? Can you even see the details from say outer space or high up in the sky? The answer clearly is no.

Also, there's plenty of ways we can make crop circles, so why assume some alien life form must have been responsible?