A bizarre freak of nature, Meteora is an outcropping of massive stone pillars, springing suddenly from a verdant plain in west-central Greece.

Legend has it these rocks were dropped from heaven, for they seem to rise from nowhere, topping heights of a quarter-mile. In fact, the name Meteora means "rocks in the air." Their irregular shapes, cleft by caves and fissures, are strewn in a random pattern, as if Henry Moore had begun a mile-square sculpture but hadn't finished it.

Contrasted against this whimsy of nature are brilliant examples of the determination of man. Perched atop these natural skyscrapers are a series of Greek Orthodox monasteries built 600 years ago and housing some of the greatest examples of Byzantine art in Greece.

Records show Meteora first being used as a spiritual stronghold in the 11th century. Hermits seeking refuge from religious persecution moved into lofty caves in the rock pillars. The first monastic community on the pinnacles was founded in the mid-14th century, and over the next hundred years 24 monasteries were built.

How this was done staggers the imagination, for the steep, sheer-sided fingers of stone offer no simple ascent. Yet the churches and hermitages cling to their rounded summits as tenaciously as barnacles, with the monks who inhabit them balanced in a spiritual plane between heaven and earth.

The first, the largest and most important monastery was the Great Meteoron, founded by the monk Athanasios in 1344. In 1388, a Serbian prince opted for an ascetic life there, and endowed it with riches and privileges, which soon gave it ascendancy over the other monasteries.

Over the next 300 years, most of the monasteries fell victim to ransacking thieves and intermonastic quarrels. Today, only five are in operation and can be visited, with a sixth under renovation. The Great Meteoron is still the most important and most beautiful.

For centuries, visiting the monasteries was a task undertaken by only the most determined, so it seems almost disrespectful to be able to drive from the nearest town of Kastra'kion to the Great Meteoron in 15 minutes. Climbing gradually through rolling hillside around the rocks, the road offers varying angles to peer up at, around and, eventually, down at the striated stone columns. Then suddenly you're in a most incongruous parking lot hacked out of the mountainside.

But the difficulty in reaching the monastery becomes evident again when you begin a climb of a couple hundred uneven stone steps. Before they and a walled path were cut into the rock face in 1923, provisions and people were hauled up in a rope net. It was an act of faith not to replace the rope until it broke. The winch and large wooden basket near the entrance are still used to transport supplies.

When you enter this most secluded meditative refuge, you are immediately struck by the beauty of it. Orange-tiled roofs are a colorful counterpoint to grayish stone walls. Wooden walkways are carefully swept, and in the center of the complex is a small garden with meticulously tended flowers.

The monastery's church, built in the 16th century in the shape of a Greek cross, is even more startling. Above the row of wooden seats along the interior wall, every inch of the walls is covered with dazzling frescoes of New Testament scenes. The Cretan style used is characterized by very bright colors and natural expressions, especially on the face of Christ in the center of the domed ceiling. The white-bearded priest who takes care of the church occasionally cants ancient Byzantine hymns when few people are around.

The monks' cells are not open to the public, but you can peer into a darkened room to see precise stacks of skulls and bones, remains of earlier residents. And you can visit the old kitchen, with brick ovens and a lingering smell of smoke. The vaulted brick refectory now houses what treasures escaped repeated robberies: illuminated manuscripts, carved wooden icons, embroidered vestments -- all done by the monks.

But man's efforts cannot rival what nature created. To remind them, the monks have a circular terrace that overlooks the Varlaam Monastery -- on the next peak -- and the entire Thessalian plain, sliced by the Pinio's River and bounded by the Pindus Mountains. Villages are scattered on its dark-green fields and fruit orchards are arranged on south-facing hillsides. It's a stunning view that makes you realize how very far you are from civilization.

Just a little way down the road, Varlaam is the next most important monastery. Built in 1518, it is known for the especially beautiful murals inside its church.

But the Monastery of St. Stephen, founded in 1350, offers a far more dramatic contrast to the others: It is now a nunnery. The central area is spacious, with whitewashed walls and clean flagstone paving. Pots of blooming plants line the walkways. The church inside is smaller, and its frescoes are almost completely ruined. But the fabulous brass chandelier makes up for that. The tiny museum displays St. Stephen's modest ecclesiastical wealth, highlighted by three gilded wooden crosses of amazing detail.

The monasteries of St. Nicolas and the Holy Trinity are smaller and less impressive in scale, but are also precariously perched on bare stone. Rousanou Monastery, which is under restoration, will be open to the public in a few years.

They all stand as startling anachronisms and tributes to man's endless ingenuity.