Residents in Huanshan City in East China have been stunned after a giant mirage of a “ghost city” towered across the skyline earlier this month.

The apparition of tall buildings, mountains and trees appeared to rise up through the ghostly mist that had descended over the river at dusk after heavy rainfall and humid conditions along the Xin’an River.

An entire island with trees, tall buildings and mountains in the distance can be seen in the dusk light

Stunned residents recorded the footage with some even suggesting that it could have been a “vortex” to a lost civilisation.

The pictures have baffled even experts who visited the city to check out the strange happening.

It is believed that the sight may have been a mirage – a form of illusion that is common in in humid weather. The phenomenon is caused when moisture in the air becomes warmer than the temperature of water below it and refracts rays of sunlight to create reflections in the sky.

The patterns in the mirage are typically blurred and shimmering with a resemblance to human structures. But this apparent mirage in China would rate as one of the clearest ever recorded.

“It’s really amazing, it looks like a scene in a movie, in a fairlyland,” said one resident.