Archaeologists first noticed the remnants of the more than 3,000-year-old enclosures in 2015 while reviewing Google Earth photos of a 93-mile stretch (150 kilometer) of wilderness along Serbia's Tisza River, according to a study published Nov. 10 in the journal PLOS One.
"We could see traces of over 100 Late Bronze Age settlements," study lead author Barry Molloy, an associate professor of archaeology at University College Dublin, told Live Science in an email. "What is fascinating about the [sites] is that we not only identified their presence in these images, but also measured their size and, for many, how people organized the layout inside their settlements."
He added, "It is quite unique in European Bronze Age archaeology to get this level of detail for so many settlements in such a specific area."
Previously, this area, known as the Pannonian Plain, was thought to be a hinterland not used for Bronze Age settlements. But now, researchers think that this is just one example of the many settlements found across Europe that are part of an extensive trade network from the time.