To answer your question, the crop circles where the residue of some radiation are found, are made by alien beings.
By the way, I know and believe in whatever you said in your comment. There are alien beings that are already here and have been here for thousands of years. We have the technology to take them to their home and back without breaking a sweat. We also have free energy devices (probably since Tesla invented it) and it has been suppressed for obvious reasons (cough the order, cough global control...). You probably also know about the shadow group of people that controls everything... like everything!! I know my blog comes across as a "mainstream blog" but that is just the way I want it to be. Personally though, "I KNOW". I have known and have been researching for like 10 years now. In fact, I am going to share some really interesting info that you will appreciate. Do some research about the anti-order. Maybe you already know about them, maybe you don't. But you should definitely learn about them. Cheers!