Archaeologists in Saudi Arabia have discovered a 4,500-year-old network of highways lined with well-preserved ancient tombs.
Researchers from the University of Western Australia conducted a large-scale investigation over the past year, consisting of aerial surveys by helicopter, ground surveys and excavations, and the study of satellite images.
The team discovered approximately 18,000 tombs along the avenues of graves, 80 of which have been sampled or excavated for research.