As one of the region's better known tourist attractions - or as some would have it - one of the great unexplained mysteries of all time - the faces of B_ez are not very well promoted. A few sporadic signposts on the road from the southern Spanish city of Jaen mark the way.

The town of B_ez de la Moraleda - set high in the mountains of Andalusia and surrounded by olive groves - is always quiet, but on a Sunday morning it is deadly. A group of about 20 old men sat in the town-square, muttering to one another, smoking or looking at the ground.

When I asked one of them where I could find the faces at least eight of them began giving directions. In a maze of narrow, cobbled streets around the church - muffled voices from dark doorways gave me further directions if I showed any sign of hesitancy. Finally I arrived at a small whitewashed cottage.

An apparition

The front door was open so I entered and found an old lady in an armchair watching a religious service on television.

"Las Caras, the faces?" I asked. "Can I see them?"

She waved me into the small, sparsely-furnished front room and continued watching television. I looked at the floor where I'd been told the faces would be. And as soon as my eyes had become accustomed to the dim lighting, I quite clearly saw the face of a young woman.

It was faint at first but gradually the definition and the details became clearer. It was a sad face. There were others - some clear, some not so clear. Images of old men and children deeply ingrained in the cement floor.

A nun arrived to treat an ailment the old woman was suffering from, so I apologised for the intrusion and left.

I could have been looking at paintings cleverly rubbed into the stone floor. But a stream of scientists have been to the house, taken away chunks of floor, applied every test available to them and discounted that theory.

The faces of Belmez have been a mystery ever since the old woman, Mar_G__ C_ra, saw the first image appear in her kitchen in August 1971.

She ran to tell the neighbours who were so disturbed that one of them chopped the image out with a pickaxe - only to see it re-appear shortly afterwards. More faces appeared and word spread.

First came the journalists and television film crews, then the religious and political authorities.

Explanations

The faces of B_ez became known all over Spain and on some days up to 5,000 people would line up outside Maria's small house for a look at this strange apparition.

Many explanations were suggested - it was some kind of religious intervention, a neighbour's son - a talented artist - was doing the drawings late at night as a joke, they were the product of some kind of radioactive leak.

What was known for sure was that the house was built in the 1830s over what had been a Christian cemetery. Before that it was a Muslim burial site and before that the Romans had lain their dead there.

The local church and political authorities were keen to put an end to the disruption caused by the growing number of visitors to the town. They were also uneasy about the fact they couldn't explain the phenomenon and sought to have the faces declared a fraud as soon as possible.

A 24-hour police guard was put on the house and any suspicious characters seen entering were questioned. Experts were brought in from Madrid to try to find out what materials the faces were made from, to analyse the stone floor, to check the earth beneath the house.

Believers and disbelievers

As news spread, members of religious cults, believers in extra-terrestrials and just the plain eccentric arrived in their hundreds.

Some observers, especially among local people, were convinced from the start that the faces were a fraud and someone was making money from them.

Others said that the owners of the house, Maria and her ailing husband, Juan - simple farm-workers - were unable to read or write, let alone fool the scientific establishment.

All Maria appears to have gained is a new kitchen - built by the local authorities since so many visitors were walking through the original kitchen - where the faces first appeared - that her family went days without eating.

In the 28 years since Maria saw the first face neither the believers nor the disbelievers have come up with conclusive proof to back their case.

Experts

Germ_de Argumosa is a Madrid-based parapsychologist who has investigated the case in depth and while he doesn't have the answers, is convinced it is not a fraud. He has brought in experts from around the world.

One of them, Professor Hans Bender from Germany, called the faces of B_ez "without doubt the most important paranormal phenomenon this century."

Leading the case for the sceptics is Jos_uis Jord_Pe__ho is convinced it is nothing more than a joke played between neighbours which got out of hand in a boring town.

The faces, he says, have been impregnated into the cement floors using a mixture of soot and vinegar. Detailed analysis found traces of both. Of course, say the believers - soot and vinegar traces will be found on any kitchen floor in the region if one looks hard enough.

As I walked back past the men who had given me directions, one of them stopped me.

"Did you see the faces? What did you think?" he asked. "Did she show you the face of General Franco under the table?" No, I replied. "Ah, that's because you didn't pay her - she wants money before she shows that one," he explained conspiratorially before rejoining his friends.

Did the men then laugh at another visitor attracted by a simple but effective hoax? A hoax that's put the otherwise uninteresting town of B_ez de la Moraleda on the map. Or are the faces of B_ez really one of the great unexplained mysteries.