Blessing or curse? New lake appears in Tunisia’s desert

Hundreds of swimmers have been flocking to a mysterious new lake in the Gafsa region of southern Tunisia. The 18-metre deep lake appeared three weeks ago and covers a hectare of the desert. Hailed as a miracle by locals, the sudden appearance of the body of water in the drought-stricken area has raised concerns about its origin and quality.

After several long hours on the road without a break, I honestly thought I was hallucinating. I don’t know much about science and thought it was magic, something supernatural.

Mehdi Bilel, who noticed the lake when driving back from a wedding in Om Larayes

One theory is that seismic activity may have created a crack in the rock above the the water table, allowing water to seep to the surface. But the change of the water from crystal blue to a sludgy green suggests the water is not circulating. Local authorities are concerned that the lake has appeared in an area rich in phosphate deposits, which may cause the water to become strongly radioactive. Samples have been sent away for testing but, with summer heat at its most brutal, a steady stream of swimmers don’t seem to be willing to wait for the results.