An enormous secret 'town' has been unearthed by thawing ice in Antarctica – but could have been buried there for years.

The discovery, made up of a long series of 'sinister-looking' structures, has sparked speculation and conspiracy theories.

Spanning more than a mile, it was spotted by an online paranormal investigator, known as 'Conspiracy Depot' on Google Earth.

He said: “I assume they are related to some man-made activities for research purposes. "But I’ve looked at the co-ordinates and I’ve looked on a number of sites for all known research stations in Antarctica and the closest one is Norwegian station 200 miles away.”

One viewer guessed the discovery is a nuclear bunker for the world’s rich and powerful elite, the Express reports.

While another speculated it is a landing pad for aliens.

The area deep inside Antarctica appears to be covered in vehicle tracks, and it also looks like there's an airstrip.

Another paranormal investigator, Florida Maquis, added to the intrigue by claiming the mystery structure remains visible in sightings going back to 2001.

He looked at the site year by year and said “this is about as creepy a place as I’ve ever seen in my life."

The investigator said it looked like a runway and some sort of operations centre.

But it remains uncertain what the site actually is.