Scientific has shown that crop circle is made by human being as hoaxes. The most known method is to use a tie of rope to create an anchor and the other end to crush plants to ground.
The famous Bower and Chorley confessed that they are the one making first crop circle in South England. Even though some refuse what they’ve heard they show a solid method of how to create one. With this effect TONS of complex circles started to appear in many country of the would usually were made at night.
He even wrote about how easy it is to develop a complex crop circle to fool on “expert” sources such as The Wall Street Journal. Many methods of creating a crop circle are now well documented on the Internet.