On October 11, 1906, residents of the city of Petaluma, California, were terrified by an unexplained phenomenon. Some thought it was a divine sign foretelling the Apocalypse.

That day the sky over that town ubicated in Sonoma County turned crimson. The clouds were completly red. The whole municipality was immersed in a surrealist atmosphere. This phenomenon lasted about 25 minutes. After that, everything returned to normal.

What happened here? There is little chance that was caused by pollution, much lower at this time. It could be a sandstorm like it happened in Arxan, northern China, in April 2015.