11 Astonishing Underground Cities Around The World, From Derinkuyu To Coober Pedy

Published September 28, 2023

Wieliczka Salt Mine In Poland

Wieliczka's Underground City

Wikimedia CommonsSt. Kinga’s Chapel deep within the Wieliczka salt mine.

Ever since ancient times, humans have sought to obtain salt. In the Neolithic era, this was done by boiling brine in small clay pots. Ancient humans used salt primarily as a method of preserving meat and fish, making it a valuable resource. As it turns out, the earliest salt-making tools found in Central Europe were discovered in the village of Barycz, near Wieliczka, Poland.

Hundreds of years after these tools were used, around the 12th century C.E., however, the salt springs began to dry up. Locals across the Wieliczka region began to dig deep wells to extract salt water and bring it to the surface for boiling, hoping once again to extract the coveted salt from the brine.

It was around the 13th century when the first chunks of salt rock were discovered — and this discovery would change the region forever.

Over the following centuries, locals continued to dig into the ground, extracting salt rocks. According to the mine’s own website, the salt excavation ended up being so profitable for the Polish crown that it constituted nearly a third of the treasury’s income.

Thankfully, the Polish king Casimir III decided to put that money to good use. He took the profit from the salt mine and put it toward civil projects, including Poland’s first university, Krakow Academy.

By the end of the Middle Ages, about 300-500 people worked in the Wieliczka salt mine, mining nearly 8,000 tons of salt each year.

And though a mine isn’t technically a city, Wieliczka is a notable exception because it remained in production for about 700 years. This extended excavation resulted in more than 2,300 underground chambers spanning over 150 miles, making it bigger than most other underground cities.

Today, the mine no longer produces salt, but it remains a massively popular tourist destination in the country, often included in the official itineraries of politicians, heads of state, and royal families who visit Poland.

author
Austin Harvey
author
A staff writer for All That's Interesting since 2022, Austin Harvey has also had work published with Discover Magazine, Giddy, and Lucid, covering topics including history, and sociology. He has published more than 1,000 pieces, largely covering modern history and archaeology. He is a co-host of the History Uncovered podcast as well as a co-host and founder of the Conspiracy Realists podcast. He holds a Bachelor's degree from Point Park University. He is based in Pittsburgh, Pennsylvania.
editor
Jaclyn Anglis
editor
Based in Brooklyn, New York, Jaclyn Anglis is the senior managing editor at All That's Interesting, where she has worked since 2019. She holds a Master's degree in journalism from the City University of New York and a dual Bachelor's degree in English writing and history from DePauw University. In a career that spans 11 years, she has also worked with the New York Daily News, Bustle, and Bauer Xcel Media. Her interests include American history, true crime, modern history, and science.
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Harvey, Austin. "11 Astonishing Underground Cities Around The World, From Derinkuyu To Coober Pedy." AllThatsInteresting.com, September 28, 2023, https://allthatsinteresting.com/underground-cities. Accessed July 24, 2025.