The circle in Raisting, upper Bavaria, has a diameter of 75 metres and is formed of three rings.
It was discovered last week by hot air balloonists and word quickly spread through internet forums of the find.
“They sang, danced, played guitar… and slept in the field,” a woman who lives nearby said of the area’s new visitors to the site, the Süddeutsche Zeitung reported.
Many visitors believe it was not formed by humans.
“This is a technology which we haven’t mastered yet," said one visitor to the newspaper. “They want to show us – we are here, we love you.”
The crop circle is near the antennas of a former communication station which was used to broadcast the first moon landing in 1969 to European households.
Christop Huttner, the farmer who owns the field, said he had not created the crop circle.
“This is very difficult [to do] and really well done,” he said. “I don’t know how they managed it. There are no tyre tracks, nothing at all.”
He said the damage to the crops had cost him a few hundred euros.
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