The crescent Moon descends through the clear Chilean sky above the La Silla observatory and hits the thickest parts of the atmosphere right above the horizon. Here the thin sliver of the Moon is optically distorted into a weird and snaky shape as its light passed through closely-spaced layers of different air density, caused by different pressure and humidity, and it makes a feel like it was swimming there. The very young Moon is followed by bright planet Venus — in the upper left part of the image — slowly moving to the horizon too.