Archaeologists working at Chleby in Central Bohemia have documented a circular enclosure roughly 230 meters across, defined by a ditch about two and a half meters deep, with twelve entrances leading into the centre. It dates to around 4500 BC, which puts it some fifteen centuries before the first earthwork was cut at Stonehenge.
A small section of the prehistoric circular enclosure at Chleby, which had twelve entrances aligned to astronomical events. Credit: University of West Bohemia
The team is led by Petr Krištuf of the University of West Bohemia, working with Jan Turek of Charles University in Prague and Jan Fišer of the University of Hradec Králové.
This is a known class of monument and the coverage does not say so
Circular ditched enclosures of this kind are one of the better-studied phenomena in European prehistory. They are called rondels, or Kreisgrabenanlagen in German, and somewhere between 150 and 200 have been identified across a belt of Central Europe running about 800 kilometers from Bavaria to Hungary. The Czech Republic alone has around fifty-five.
They belong mainly to the first half of the fifth millennium BC and to the Stroke-ornamented Pottery and Lengyel cultures. Most are between forty-five and 180 meters across, with a V-shaped ditch, palisades, and usually two to four narrow entrances.
They are also, as a class, astronomically aligned. That is the standard interpretation, not a novel one. The best known is Goseck in Saxony-Anhalt, built around 4900 BC, seventy-five meters across, with three entrances, two of which frame sunrise and sunset at the winter solstice. Goseck is routinely described as Europe’s oldest solar observatory and it is four centuries older than Chleby.
So older than Stonehenge is true of Chleby and true of dozens of other monuments in the same tradition.
What is genuinely unusual is the size, the number of entrances and the date
Against that background, three things about Chleby stand out.
Two hundred and thirty meters is well beyond the normal range. Twelve entrances is several times the usual number. And the date sits after the main rondel horizon, which ran from roughly 4900 to 4600 BC and then stopped.
That last point is what Krištuf appears to mean when he says circular enclosures of this period are not known in the region. The classic rondels had ended by then. Chleby belongs instead to a looser, later group that specialists have called rondeloids, and it has in fact appeared in that literature before, alongside sites in Moravia, Slovakia and Bavaria.
Twelve entrances aligned to the sun and the moon
Krištuf says the arrangement of the entrances stopped looking random once the team analysed it in detail, and that their geometry forms a system for observing the most important moments in the solar and lunar cycles.
The solar alignments are the familiar ones, sunrise at the summer solstice and sunset at the winter solstice. Krištuf reads that pairing as a beginning and an end, and points to the same principle in the main axis at Stonehenge.
The lunar claim is the larger one. It concerns the moon’s 18.6-year cycle, over which the extremes of its rising and setting positions swing back and forth along the horizon before returning. Tracking that requires observation sustained across a generation. Alignments to it have been proposed at a number of prehistoric sites and are harder to establish than solar ones, because the moon’s extreme positions are reached rarely and the margin for coincidence is correspondingly wider.
Bulls at the gates
The enclosure walls were probably built from wooden posts. Animal bone recovered from the ditch has led the team to suggest the entrances were decorated with bull skulls and horns.
Turek places this within a wider pattern. The bull cult was a significant religious symbol among early farming communities and is known from many parts of prehistoric Europe, with bulls most likely standing for strength and fertility.
The site kept being used for another four thousand years
Whatever the enclosure meant, the meaning did not hold.
Earlier excavation at Chleby recovered burials of eighteen people belonging to the Únětice culture of the Early Bronze Age, roughly 2300 to 1600 BC, the culture that produced the Nebra Sky Disc. The site may still have been ritual at that stage.
By the Iron Age it was not. A settlement was built over it, the ditch was gradually filled in, and Krištuf’s assessment is that the monument had lost its original significance entirely by then.
What comes next is soil chemistry
The work is continuing, and the team plans to analyse the soil.
Fišer’s point is that people leave chemical traces behind as well as objects and bodies, and that reading those traces may show how this unusual site was used across the different phases of its long life.
Source. Live Science, 25 August 2026, with comment from Petr Krištuf, Jan Turek and Jan Fišer. Comparative material on Central European rondels from published surveys of the monument class and from the Goseck excavations.