Clashes between Islamic State and the Syrian regime are threatening the 2,000-year-old ruins of Palmyra, the latest of the region’s historic sites in danger of being destroyed in the country’s conflict.

In recent days, Islamic State has advanced from its strongholds in the east to seize control of villages surrounding the ruins and adjoining town in central Syria, according to residents and opposition groups.

Palmyra dates back to the first century, according to Unesco, the United Nations’ cultural agency, which has called it one of the most important cultural sites in the Middle East. The site includes a Roman colonnaded street and the temple of Baal, a deity worshiped in many ancient Middle East communities. […]