I've know about crop circles and the Nazca lines since I was very young and I thought this was common knowledge. I was surprised that my collegues didn't know about them and only recently discovered there's such a thing.
The only new thing I got to know about crop circles is they are still appear as late as 2009. I thought these are lines form in the distant past, long long ago. Very surprised that they are still appearing now.
So, have you heard of crop circle before? Those patterns are amazing and they are not man-made.