The ring ... mysterious cloud in Mexico
The astonishing ring was spotted over the central American state and video of it was posted on the internet prompting speculation its cause was extra-terrestrial.
It is the SECOND time such an amazing sighting has been seen after The Sun revealed one was recorded in skies over Moscow last October.
Scores of supernatural enthusiasts have been gripped by the astonishing footage and speculated it could be an ALIEN MOTHERSHIP.
Others believe it could be a porthole for UFOs to enter or leave the Earth's atmosphere.
Or that a meteorite pierced through a cloud before crashing to Earth.
The sighting in the clouds is reminiscent of scenes from the 1996 Hollywood blockbuster Independence Day.
The circular white cloud was filmed against a blue sky was taken in Mexico on February 11 according to the YouTube post.
A message on the video sharing website reads: "Amazing footage shows what may have been a UFO entering or leaving our Earth."
It has been described as a "true mystery" by a UFO expert Nick Pope - who investigated the phenomena for the Ministry of Defence.
He added: "It's amazing. The similarity with the so-called halo cloud seen recently over Russia is striking. One possibility is that a meteorite or fireball punched through the cloud.
"This could explain the strange sound reported and the fact that a crater was apparently found.
"Speculation is rife on the internet - aliens, secret weather modification technology, or even some distortion of reality, caused by the Large Hadron Collider."
Even weather experts have been left dumbfounded by the extraordinary sighting.
A Met office investigator examined the freak sighting and said its cause is "unknown".
Sarah Holland, Met Office spokesman, said: "This is what is called a fallstreak cloud, otherwise known as a holepunch cloud.
"It's where patches of high cloud formed by super-cooled water freeze and fall away as ice crystals leaving a visible gap in the cloud layer.
"Aircraft exhausts could play a part in the freezing process but the precise cause is unknown."
Video of the Moscow halo became an internet sensation attracting more than a MILLION hits.
However Russian weather experts claimed it may have been due to several weather fronts colliding over Moscow.