Could this be a mysterious floating city that was “seen by hundreds of people across the globe?”
An alleged video recording of the event went viral online before details of similar sightings in other parts of the globe emerged.
The massive anomaly captured by the NASA live feed.
In a promotional video blurb, Streetcap1 said: “I thought I was seeing things at first then quickly started recording. To my surprise they cut transmission – attempt at a joke – anyway this has to be huge whatever it is. If it were a building it would be hundreds of miles long.”
Viewers of his channel were impressed and one speculated if it could be “alien related”.
One posted: “They are here! I wonder when they are going to make their great entrance on a major city, and the people’s reaction.”
Another called added: “There IS something there and its very odd.”
But many people believe the alleged object is nothing more than a reflection from the Sun.
These include Scott Brando, a UFO hoax investigator, who runs ufoofinterest.org.
He told Express Newspaper: “I think is a reflection of sunlight through clouds.”
He pointed to an explanation he gave to a similar alleged sighting following a similar effect.
In fact, most people believe the original city in the sky event was also an optical illusion known as fata morgana which can lead to objects such as boats or buildings appearing to be disembodied from the surface of Earth.
NASA last month also spoke for the first time about why its live feeds occasionally lose power, following a string of “false” claims it was covering up UFO encounters with the ISS.