As part of their survey, researchers examined declassified U.S. spy satellite imagery from the 1970s, which is now in the public domain, and compared the visual data to modern-day photography and historical texts to understand the stopping points along the Hajj pilgrimage route.

U.S. spy satellite imagery has led archeologists to what they believe is the site of a seventh-century battle that was decisive in the spread of Islam in the region.

Archaeologists from Durham University and University of Al-Qadisiyah in Iraq have pinpointed the location of a famous early Islamic battle using declassified spy satellite images.