Across the world, ancient civilisations built vast underground cities—some capable of housing thousands. From Turkey to China, the Grand Canyon to Antarctica, these hidden metropolises raise a compelling question: Why did so many cultures, separated by continents, choose to go underground?

 

Global Network of Hidden Cities

• Turkey (Derinkuyu & Kaymaklı, 5000+ years old): Housed up to 20,000 people, possibly built for defense against invaders.
• Iran (Nushabad, 1500+ years old): A hidden, three-level refuge from war and extreme heat.
• Egypt (Hawara Labyrinth, Age Unknown): Alleged to contain 3,000 underground rooms, possibly holding sacred knowledge.
• Ecuador (Cueva de los Tayos, Age Unknown): Mysterious smooth tunnels explored by Neil Armstrong in 1976.
• China (Underground Great Wall, Age Unclear): Ancient texts reference entire underground fortresses.
• Grand Canyon (Tunnels, 1909 Report): Claims of hidden caverns filled with lost artefacts.
• Antarctica (Frozen Tunnels, Age Unknown): Satellite images hint at vast underground structures beneath the ice.

Why Did They Go Underground?

1. War & Survival: Many sites served as defensive hideouts from invaders.
2. Climate Catastrophes: Volcanic eruptions, droughts, or an Ice Age may have forced people below.
3. Cosmic or Geological Events: Some believe ancient civilisations were protecting themselves from unknown dangers.
4. Lost Advanced Civilisations?: The precision of certain structures hints at sophisticated lost knowledge.

 

When we examine these sites on a historical timeline, a pattern emerges:

• 5000+ years ago: Turkey’s Derinkuyu and the Egyptian labyrinth.
• 2000–1500 years ago: Iran’s Nushabad, China’s underground defenses.
• ? years ago: Ecuador’s Cueva de los Tayos and rumored Grand Canyon tunnels.
• Antarctica? Could frozen tunnels hold clues to an even older civilization?

 

How did civilizations separated by oceans and continents all develop massive underground structures? Was it shared knowledge, independent invention—or something more?

A Hidden Past Yet to Be Uncovered

With radar scans detecting unexplored subterranean structures, could more underground cities be waiting to be found? Did ancient people know something we don’t? And if so, are we destined to return below once again?

 

22 hours ago, CharlieH said:

When we examine these sites on a historical timeline, a pattern emerges:

• 5000+ years ago: Turkey’s Derinkuyu and the Egyptian labyrinth.
• 2000–1500 years ago: Iran’s Nushabad, China’s underground defenses.
• ? years ago: Ecuador’s Cueva de los Tayos and rumored Grand Canyon tunnels.
• Antarctica? Could frozen tunnels hold clues to an even older civilization?

What's the pattern?

Turkey and Egypt, somewhat neighbors...

3000 years later China and Persia, somewhat neighbors...

Couple of question marks...

and still the stated "pattern" eludes me.

iceage brought upon by asteroid hitting earth and blacking out the sun?? they can tell the history of the planet by looking at ancient tree ring growth and studying strata in rocks...

Sounds like the Netflix series Ancient Apocalypse by Graham Hancock, he also tries to create an image where everything is connected to a lost advanced civilisation

https://en.wikipedia.org/wiki/Younger_Dryas

 

Graham Hancock puts a lot of happening down to the Younger Dryas event.

 

I've been to/in Derinkuyu in Turkey, just south of Capadocia. 

The local guides say it was used when the invaders came and the whole village with animals could go underground for up to 2 years but they don't say who built it,

It is a massive underground structure carved into granite, whoever built it had a LOT of time