DEMRE, TURKEY

In the 4th century A.D., a bishop named Nicholas transformed the city of Myra, on the Mediterranean coast of what is now Turkey, into a Christian capital.

Nicholas was later canonized, becoming the St. Nicholas of Christmas fame. Myra had a much unhappier fate.

After some 800 years as an important pilgrimage site in the Byzantine Empire, it vanished -- buried under 18 feet of mud from the rampaging Myros River. All that remained was the Church of St. Nicholas, parts of a Roman amphitheater and tombs cut into the rocky hills.

But now, 700 years later, Myra is reappearing.

Archaeologists first detected the ancient city in 2009 using ground-penetrating radar that revealed anomalies whose shape and size suggested walls and buildings. Over the next two years they excavated a small, stunning 13th-century chapel sealed in an uncanny state of preservation. Carved out of the eastern wall is a cross that, when sunlit, beams its shape onto the altar. Inside is a vibrant fresco that is highly unusual for Turkey.

The chapel's structural integrity suggests that Myra may be largely intact underground. "This means we can find the original city, like Pompeii," said Nevzat Cevik, an archaeologist at Akdeniz University who is director of the excavations at Myra, beneath the modern town of Demre.

Mark Jackson, a Byzantine archaeologist at Newcastle University in England, who was not involved in the research, called the site "fantastic," and added, "This level of preservation under such deep layers of mud suggests an extremely well-preserved archive of information."

Occupied since at least the 4th century B.C., Myra was one of the most powerful cities in Lycia, with a native culture that had roots in the Bronze Age. It was invaded by Persians, Hellenized by Greeks and eventually controlled by Romans.

Until the chapel was unearthed, the sole remnant of Myra's Byzantine era was the Church of St. Nicholas. (The bishop, also known as Nicholas the Wondermaker, was a native Lycian of Greek descent.) First built in the 5th century A.D. and reconstructed repeatedly, it was believed to house his remains and drew pilgrims from across the Mediterranean. Today, Cyrillic signs outside souvenir shops cater to the Russian Orthodox faithful.

But Myra attracted invaders, too. Arabs attacked in the 7th and 9th centuries. In the 11th, Seljuk Turks seized the city, and the bones thought to be those of Nicholas were stolen away to Bari, in southern Italy, by merchants who claimed to have been sent by the pope.

By the 13th century, Myra was largely abandoned. Yet someone built the small chapel using stones recycled from buildings and tombs.

Decades later, several seasons of heavy rain appear to have sealed Myra's fate. The chapel provides evidence of Myra's swift entombment. If the sediment had built up gradually, the upper portions should show more damage; instead, except for the roof's dome, at the surface, its preservation is consistent from bottom to top.