(CNN) A sprawling 3,400-year-old city emerged in Iraq after a reservoir's water level swiftly dropped due to extreme drought.
Kurdish and German archaeologists excavated the settlement in the Mosul reservoir, along the Tigris River in the Kurdistan region of northern Iraq, in January and February. The project was in partnership with the Directorate of Antiquities and Heritage in Duhok to preserve the area's cultural heritage for future generations.
The archaeological site, Kemune, is believed to be the Bronze Age city Zakhiku, a major hub of the Mittani Empire that reigned from 1550 to 1350 BC. The kingdom's territory stretched from the Mediterranean Sea to northern Iraq, according to Ivana Puljiz, junior professor in the department of near eastern archaeology and assyriology at the University of Freiburg in Breisgau, Germany, and one of the directors of the project.
Zakhiku was submerged underwater after the Iraqi government built the Mosul Dam in the 1980s and has rarely seen the light of day since then.
After Puljiz heard the city had reemerged, her team hurried to excavate the site because it was unknown when the water levels would rise again.
"Due to the enormous time pressure, we dug in freezing temperatures, snow, hail, rain, even storms, as well as the occasional sunny day, not knowing when the water would rise again and how much time we would have," Puljiz said.
The ancient city is now resubmerged, but researchers were able to catalog much of the site.
A palace had already been documented when the city briefly emerged in 2018, but multiple additional structures were documented during the latest excavation. Some of the discoveries include a fortification complete with towers and walls and a storage building multiple stories tall.
Much of the structures were made of sun-dried mud bricks, which ordinarily would not hold up well underwater, researchers said. However, Zakhiku suffered from an earthquake around 1350 BC, and parts of the upper walls collapsed and covered the buildings.
Little is known about the ancient Mittani people who built the city, largely due to the fact that researchers have not identified the empire's capital or discovered their archives, Puljiz said. However, certain artifacts unearthed during the latest excavation could help provide insight.
Archaeologists found five ceramic vessels holding over 100 clay cuneiform tablets, dating back to closely after the earthquake event. They are believed to be from the Middle Assyrian period, which lasted from 1350 to 1100 BC, and could shed light on the city's demise and the rise of Assyrian rule in the area, according to a news release.
"It is close to a miracle that cuneiform tablets made of unfired clay survived so many decades under water," said Peter Pfälzner, professor of near eastern archaeology at University of Tübingen and one of the excavation directors, in a statement.
The tablets have not yet been deciphered, but Puljiz hypothesized they belonged to a private archive.
"I am curious next to see what the study of the cuneiform texts will reveal about the fate of the city and its inhabitants after the devastating earthquake," she said.
All artifacts that were excavated, including the tablets, are being housed in the Duhok National Museum.
Before the city once again disappeared underwater, researchers covered the ruins in tight-fitting plastic sheets held down with stones and gravel. Puljiz hopes these measures will protect the ancient site from water erosion and prevent it from disappearing altogether.