Sometimes there are weird phenomena that clearly form in front of our eyes, but aren’t real, like dreams or mirages!
These pictures look like a giant tidal wave crashing onto people on a beach in the UK, but are actually the result of an amazing and somehow terrifying optical illusion.
Here the explanation by Les Cowley from Atmospheric Optics:
Cley on the English Norfolk coast has a picturesque windmill and a 7 mile long, high shingle spit. The raised spit and gentle wind from the cold sea and are the keys to this complex mirage.
On the left side of the picture there are patches of sky mixed with the distant shingle. This is the familiar ‘hot road’ mirage. Light rays bend as they pass between layers of air cooled by the sea and heated by the sun-warmed shingle. The scene is chaotic and changing as the air layers become turbulent. That’s the easy part!
The mirage gets more complicated because in places rays pass through at least three air layers. There is sea-cooled air under spit-warmed air beneath a higher layer of cool air. The layers tilt as air drives upwards over the spit. Light passing through this complex thicket of thermal layers produced a fearsome-looking tsunami.
A MIRAGE tsunami wave just crashed onto a UK beach and and nobody was able to see it!