A 4,500-year-old highway network lined with well-preserved ancient tombs has been discovered by archaeologists in Saudi Arabia.

After carrying out a wide-ranging investigation last year, researchers from the University of Western Australia have made the discovery.  

The discovery have been published in Holocene journal in December.  

The team had conducted excavation, ground survey, aerial surveys with the help of helicopter and examination of satellite imagery.  

“The people, who live in these areas, have known about them for thousands of years. “But I think it wasn’t really known until we got satellite imagery that just how widespread they are,” researcher Matthew Dalton told.  

These tombs are either in the shape of pendants or rings. The pendant tombs have ‘beautiful tails’ while the ring tombs have a cairn surrounded by a wall of up to two meters in height.

With the help of radiocarbon dating, the researchers found that a concentrated group of samples dated back to between 2600 and 2000 BC. The team observed around 18,000 tombs along the funerary avenues.  

“These tombs are 4,500 years old, and they’re still standing to their original height, which is really unheard of. So, I think that’s what particularly marks Saudi Arabia out from the rest of the region — just the level of preservation is unbelievable,” researcher Melissa Kennedy.