One of the grandest engineering marvels of the ancient world—the Great Dam of Marib in central Yemen—has been damaged in an airstrike, according to local news reports and archaeological experts in touch with local sources.

Ancient Marib was the capital of the wealthy caravan kingdom of Saba (biblical Sheba, home of the legendary queen), which thrived during the first millennium B.C. Along with remains of the Great Dam, considered the most important ancient site in Yemen, excavations of the Sabaean capital have revealed two elaborate pre-Islamic temple precincts dedicated to Almaqah, the chief deity of the kingdom.

Thousands of inscriptions identified in Marib are providing researchers with an unusually detailed insight into the kingdom’s laws, institutions,