You are traveling through another dimension, a dimension not only of sight and sound but of mind, a journey into a wondrous land whose boundaries are those of imagination—and large parts of southern England. It is a land of baffled scientists, incredulous farmers, wide-eyed tourists—and mysterious, flying saucer-size circles stamped on the ripening fields of Hampshire and Wiltshire.

The phenomenon has occurred every summer since 1976. Farmers say ghostly lights appear above the land by night, and perfectly symmetrical rings are found pressed into the crops the next day. Theories about the circles, which still engage the attention of serious scientists, abound. Physicist Terence Meaden, of the Tornado and Storm Research Organization, says the cause is "atmospheric plasma vortices," or spinning ionized air masses. Other explanations range from the zoological (amorous deer and crazed hedgehogs) to the barely logical (a UFO parking lot for nearby Stonehenge).

Hoping to catch the circle-makers in action, crews from the British Broadcasting Corporation and Japan's Nippon Television Network have set up about $2 million worth of high-tech gear on the Salisbury Plain. While one Fleet Street tabloid has offered an $18,500 reward for anyone who can solve the mystery, other papers are feverishly trying to expose the whole thing as a hoax. Last week the tabloid The People ran a how-to story by a man who claims he has been flattening fields for 47 years.

While the circles haven't damaged crops much, the hordes of trampling tourists have, so some farmers are reaping profits by hawking T-shirts and offering tours of their fields. Still, there are those who have their minds on higher things than money. "There is something here, you can't deny that," says BBC producer David Morgenstern. "It is more tangible than the Loch Ness monster." The search for intelligent life continues.