Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles.

The ornate design was discovered by a balloonist last week and news of the find quickly spread online.

Farmer Christoph Huttner, who owns the wheat field near Weilheim, couldn't be reached for comment Wednesday but told the dpa news agency Tuesday he didn't create the circle himself.

He suggests students on summer holiday may have cut the image with a 75-metre diameter into his field.

The news agency says thousands of visitors have come to sing, dance and even swing pendulums in the giant image.

Huttner says he's not yet sure whether he will leave the circle in his field.