Archaeologists have discovered what they believe to be the largest ancient Christian church in Syria.
The remains of the building, thought to date back some 1,500 years, were found in Palmyra in central Syria.
A small amphitheatre and two rooms for Christian rituals were also found on the site of the church.
Palmyra, 220km (135 miles) north-east of Damascus, was an important Roman-era desert stop for caravans travelling to Mesopotamia and Persia.
Much of the city was destroyed by the Romans in the third century, in revenge for rebelling against their rule under Syrian Queen Zenobia.
The site remains a treasure trove for archaeologists.
The director of Palmyra museum, Walid Assad, said the latest find by Syrian and Polish archaeologists was the fourth church to be discovered in the city - and the largest in Syria.
Its base measures 12m by 24m (39ft by 79ft) with 6m-high (20ft) columns, the AFP news agency reports.
"Christianity came to Palmyra in the year 312, at a time when Christians had begun to build churches," Mr Assad told AFP. "And this one is huge - the biggest ever found in Syria. It dates back to the fourth or fifth centuries after Jesus Christ."
He said archaeologists found two rooms on one side of the building and an amphitheatre in the courtyard that may have been used for baptisms, prayers and other religious ceremonies.