History making discovery found in the ancient Russian city, Derbent

Buried underneath a 5000 year old city on the Caspian Sea coast, a discovery has been made that scientists say could be history-making.

Inside an ancient Russian City, the World Heritage site of Durban on the Caspian Sea’s coast has been hiding a mysterious building.

Scientists may have discovered one of the oldest Christian churches in the world by using muon radiography to scan a subterranean building buried deep in the ancient Russian city.

Archaeologists have long wondered exactly the purpose the building served and one hypothesis is that it was some type of temple. Other possible theories for the building’s function: a reservoir or a Zoroastrian fire temple.

The 11-metre high building, located in the northwest sector of the medieval fortress of Naryn-Kala, is almost completely hidden underground and built of locally sourced shell limestone; it dates to about 300 A.D.

Excavating could endanger the UNESCO site, so archaeologists have not been able to fully access the structure.

Instead, researchers from the Russian Academy of Sciences, Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, and Dagestan State University harnessed a non-invasive technique — muon radiography — to produce an image of the buried building.

If they can fully understand its structure, perhaps they could determine its use.

View from the top of the mystery building in Naryn-Kala. Picture: NUST MISIS

The results showed that the building is in the shape of a cross, furthering the belief that it could be a church. The space was found to be 11 metres high, 15 metres long and 13 metres wide.

“It seems very strange to me to interpret this building as a water tank. In the same fortress of Naryn-Kala, there is an equal underground structure of 10 meters depth, and it really is a tank,” Natalia Polukhina, head of the scientific group and the study’s author, said in a statement.

“This is just a rectangular building. The unusual building, in which we have put our detectors, has the shape of a cross, oriented strictly to the sides of the world, one side is 2 meters longer than the others.

3D-model of the underground room, obtained from the results of muon detection. Picture: NUST MISIS

“As the archaeologists who began excavations say, during construction, the building was entirely on the surface and it stands on the highest point of the Naryn-Kala.

“What is the sense to put the tank on the surface, and even on the highest mountain? It is strange. Currently, there are more questions than answers,” she added.

The study’s authors also emphasise that more muon detectors will need to be installed, in particular on the western slope of the fortress, in order to obtain a full-size underground picture.

Their work was published in the journal Applied Sciences.

This article originally appeared on Fox News and has been republished with permission.