Onlookers, some who are said to have videoed the bizarre event, were said to be mesmerised as a towering city of sky scrapers appeared from the clouds.
First thousands reportedly saw a ghostly alien city floating over Foshan in the Guangdong province of China.
A few days later people in the province of Jiangxi, China, also reported seeing a similar cloud city.
Weather experts have explained the phenomena as natural mirage, an optical illusion called Fata Morgana.
Fata Morgana can be seen on land or sea and involves the optical distortion and inversion of distant objects such as boats, which can appears as skyscrapers because the images become stacked, when rays of light bend as they pass through air of different temperatures such as in a heat haze.