In December 2016 it was widely reported that archaeologists working in northern Brazil on the banks of the Rego Grande river had discovered a large circle of standing stones.
The circle has a diameter of 30m (98 feet) and comprises 127 stones. Each stone is approximately 4m (13 feet tall) and somewhat irregular in shape.
The stones are believed to have been arranged in the circle c.1000 years ago, which has raised questions about previously unknown ancient civilisations.
There is some evidence that the stones have some astronomical basis, with the shadow of one stone disappearing during the winter solstice. If this is the case, the sophistication of Pre-european civilisations in South America was more advanced than previously thought.
The circle is now in the Parque Arqueológico do Solstício (Solstice Archaeological Park).