Numerous artifacts from the second and third centuries AD were discovered in an underground city in Mardin, Turkey, The Daily Sabah reported on Tuesday.
According to Ancient Origins, the researchers believe the underground Turkish city may be the largest in the world.
During excavations in the Midyat district, a cave was discovered containing passageways and corridors, silos, water wells and places of worship, the report added.
Gani Tarkan, director of the Mardin Museum, who heads the excavations, said that while similar underground cities have been uncovered in Anatolia, the city in Midyat is completely different, The Daily Sabah added.
"Midyat has been used uninterruptedly for 1,900 years. It was first built as a hiding place or escape area," he said. "As it is known, Christianity was not an official religion in the second century.
"Families and groups who accepted Christianity generally took shelter in underground cities to escape the persecution of Rome or formed an underground city," Tarkan added. "Possibly, the underground city of Midyat was one of the living spaces built for this purpose. It is an area where we estimate that at least 60-70,000 people lived underground."