An unusual upside down rainbow was spotted over Swansea on Thursday night.
The multi-coloured arc left residents across the city confused as it appeared in the shape of a 'U' rather than, well a rainbow shape!
People reported seeing it from Birchgrove, Fforestfach, Sketty, Clydach and even Rotherslade.
How did it occur?
According to the Met Office , the upside down rainbow is actually a circumzenithal arc.
The upside down rainbows appear when the sunlight refracts through ice crystals in cirrus clouds.
This type of rainbow is quite common but we usually can't see them because of the clouds underneath.
Grahame Madge, a spokesman for the Met Office, said: "I suspect that residents may have seen a circumzenithal arc, a feature caused by sunlight refracting through ice crystals in cirrus clouds.
"Cirrus are a high-altitude cloud, composed of ice crystals. These arcs are quite frequent but are often obscured by other lower altitude cloud.
"The conditions across South Wales yesterday evening would have given skywatchers a good chance of seeing them."
What is a circumzenithal arc?
Sometimes known as a Bravias' arc, they are formed when sunlight refracts through horizontal ice crystals at such an angle that the light enters the crystal through its flat top face and exits though a side prism face.
In order to be able to see a circumzenithal arc, a combination of atmospheric conditions must coincide.
The height, depth and position of the ice clouds must be right as the cloud needs to be at a specific angle to the sun.
The position of the observer is also important since its visibility can vary greatly over short distances.
