A photo taken in March 2014 shows Syrians riding their bicycles in the ancient oasis city of Palmyra, 130 miles northeast of the Syrian capital, Damascus. (Joseph Eid/AFP/Getty Images)

Last year, the Islamic State captured Palmyra, an ancient desert city in the heart of Syria and a UNESCO World Heritage site, and set about killing local civilians and targeting those suspected of collaborating with the regime. The jihadists' ghastly track record of demolishing and desecrating priceless pre-Islamic antiquities also raised fears of what may happen to the vast archaeological complex at Palmyra.

[Why the ancient city of Palmyra matters.]

The capture of the city and its ancient ruins "sent shockwaves through the archaeological community, which fears for the fate of the remarkable antiquities of the site," said Carol Meyers, professor emeritus of religion at Duke University, in an e-mailed statement last May. "At risk are the magnificent structures visible above ground and also the untold numbers of invaluable artifacts that lie unexcavated beneath the surface, ripe for plucking by plunderers who would sell them to fund [Islamic State] operations."

A picture taken on March 14, 2014 shows the Temple of Baal Shamin seen through two Corinthian columns in the ancient oasis city of Palmyra, 215 kilometres northeast of Damascus. (JOSEPH EID/AFP/Getty Images)

Their fears proved all too real in the months that followed. In June, the jihadists reportedly destroyed the sacred Lion of Athena; a month later, reports indicated that a number of other treasured busts and statues had been either desecrated or pulverized.

Then, in August, there was news of the reported beheading by jihadists of the octogenarian Syrian archaeologist who had studied and worked to protect Palmyra's antiquities. Then came news of the destruction of the Temple of Bel, the most significant single site in the complex, preceded by reports that the Islamic State had "blown up" the Temple of Baal Shamin, one of the historic, nearly 2,000-year-old structures within Palmyra's archaeological complex.

[Islamic State destroys priceless Palmyra antiquities]

The Roman-era temple, built in honor of a Phoenician storm god, was just one of myriad examples of the many different traditions and cultures that found a home the ancient city.

There are records of Palmyra's existence in biblical texts; the city became a thriving crossroads for trade around the 1st century A.D. and later came under Roman rule. As a result, it is layered with the overlapping histories of a number of civilizations, from Rome to Persia. UNESCO, the United Nations' cultural agency, says Palmyra "offers the consummate example of an ancient, urbanized complex." Here are some of the testaments to that rich legacy now in grave peril.

The Temple of Bel

Camels are seen in front of the Temple of Bel in Palmyra in October 2010. (Omar Sanadiki/Reuters)

This famous temple, dedicated to the Semitic deity Bel (also spelled Ba'al), is an enormous structure that combines Greco-Roman styles with more indigenous traditions. The interior roof of the 2,000-year-old building is etched with ornate carvings. This was probably the primary religious site in the city — Bel was considered a protector of caravans —  and the staging point for important cultural and civic processions.

The grand colonnade

A view of Palmyra's renowned ruined colonnade, taken in March 2014. (Joseph Eid/AFP/Getty Images)

A dramatic, half-mile long avenue of porticoed columns and arches known as the "grand colonnade" leads from the Temple of Bel to other parts of Palmyra. It was the main thoroughfare of the city and offers a dramatic glimpse of its ancient majesty.

The Valley of Tombs

A general view of Palmyra's famous graves. (Stringer photo/Reuters photo)

Several funerary monuments and tower-like tombs that abut the ruined city speak to the wealth and influence of the merchants and city-dwellers who could afford them.

The amphitheater

The theater at Palmyra, photographed in March 2014. (Joseph Eid/AFP/Getty Images)

This ancient amphitheater was partially restored by Syrian authorities in the mid-20th century.

Hadrian's Gate

The ruins of Hadrian's Gate in Palmyra, photographed in May 2010. (Mohamed Azakir/Reuters)

This triumphal arch is named for the Roman emperor who visited Palmyra in 129 A.D. and conferred upon it the status of a "free" metropolis within the empire, a sign of the city's grandeur at the time.

This post, originally published in May, has been updated to include more recent developments.

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Islamic State militants released images purportedly showing the pagan Baal Shamin temple in Palmyra, Syria, being blown up. (Reuters)