Reconstruction of circular ditches at Heldenberg, Lower Austria. Photo: Wikimedia Commons
The mysterious millennia-old sites are currently being surveyed by experts who believe they once served both as a giant calendar and a place for rituals.
It appears that circa 5,000 BC there was a large circular area in a field on the southern outskirts of Rechnitz, surrounded by wooden poles. It was only after aerial photographs were taken of the district that remnants of an ancient trench system became visible.