An image from the website.CORONA.CAST.UARK.EDU

The Middle East is home to 4,500 archaeological sites, or so we thought. An in-depth review of Cold War-era photos taken by spy satellites has pulled back the veil on as many as 10,000 more lost cities, roads, and other ruins in the region.

As Gizmodo reports, CORONA served as the code name for America’s first use of photographic spy satellites, and was in operation from 1960 to 1972.

Its name lives on in the new CORONA Atlas of the Middle East, which made its debut Thursday at the annual gathering of the Society for American Archaeology and revealed “completely unknown” sites via some of the 188,000 declassified photos taken during the mission’s final five years, reports National Geographic.

Archaeologist Jesse Casana of the University of Arkansas describes some of the sites as “gigantic,” with two sprawling over more than 123 acres; Casana suspects the largest, which appear to include aged walls and citadels, were Bronze Age cities.

And as he explains, the photos’ age matters. Though current satellites produce images superior to these grainy decades-old ones, “we can’t see a site that someone has covered up with a building,” and the fact that they were taken before cities like Iraq’s Mosul and Jordan’s Amman swelled makes them invaluable.

The CORONA site explains that the mission’s satellites snapped images “of most of the Earth’s surface” (images whose film strips were, in a great detail noted byNational Geographic, sent back to Earth via parachute-topped buckets) and archaeologists plan to also review areas like Africa and China.