I still have an open mind about the discovery of what looks like a pyramid in the sea off Japan, but these mysterious stone circles are natural.
In some remote polar regions such as Spitsbergen (image above) there are stone circles, polygons, islands and stripes made from stone over hundreds of years of winter freezing and summer thawing.
As ice forms on the surface, water is sucked up from the underlying soil by capillary action and more soil is pulled upwards to take its place. As a result of this process, known as frost-heave, the bumps push upwards and displace loose stones lying on the surface. The stones collect in a circle up to two metres wide around each bump.
Scientists estimate that it could take up to 500 years for a pattern to form from scratch.
When a second mechanism interacts with the frost-heave, the soil around the stone piles are squeezed when the soil freezes and swells. If the squeezing is strong, avalanches of stones form lines and polygons.
Different conditions create the other patterns: if the stones are sparse, they collect in islands, if the ground is sloped, the stones gather into stripes.