Namibia

In Namibia’s desert, there are bare rings in the sand, and scientists disagree about why.

On the grassy plains at the edge of the desert lie thousands of circles where nothing grows, as if someone had punched them out. They are called fairy circles

One research team argues that sand termites eat the roots of the grass, so rainwater sinks down and stays in the sand beneath the ring. Another argues that the grass itself draws the water in, leaving patches where nothing can grow.

Researchers have dug in the sand, measured and published for more than ten years. The rings are still there, and no one can yet say beyond dispute why.