NAN MADOL: The City That Shouldn't Exist – Part 1

Pohnpei is a small volcanic island lost in the western Pacific: it measures just 334 km² and is only 23 kilometers wide at its widest point . Approximately 81% of the territory is mountainous , another 14% is occupied by mangroves and wetlands , while just 5% is made up of flat land : just over 16 km² . In such an environment, especially in ancient times, we would expect a relatively small population, distributed among small coastal settlements and fishing villages. A stable population of around 10,000–14,000 people would already represent a considerable presence for an area of these characteristics.

Pohnpei is not an island just a few miles off the coast of a continent: it is surrounded by the Pacific Ocean. Guam is also about 920 kilometers away , while to reach a large landmass like New Guinea you have to cross about 1,700 kilometers of ocean .

On an island of little more than three hundred square kilometers, with very little flat land and separated from the mainland by vast sea distances, one would naturally expect to find a few coastal villages, canoes, light dwellings, and a society adapted to fishing and local resources. Instead, we find over a hundred artificial islets, monumental walls, and gigantic basalt structures .

This city exists, and it's called Nan Madol. It's built almost entirely of enormous volcanic basalt columns, stacked and interlocked to create walls, platforms, terraces, and monumental complexes. The ancient city is partially submerged.

The basalt used at Nan Madol has an average density of about 2,800–3,000 kilograms per cubic meter. If we consider not only the monumental area visible today, but also the submerged structures, those hidden in the forest, and the platforms that may have belonged to a much larger city originally, the total volume of stone used could reach about 4.5 million cubic meters. Translated into weight, this means something on the order of 13 million tons of basalt .

To understand the scale, a simple comparison is enough. The Great Pyramid of Giza is generally estimated to have weighed around 6 million tons. If these estimates for the Great Nan Madol were correct, the total amount of stone used in the Pacific city would be more than double. And all of this would have been accomplished on a remote island, without draft animals, without mechanical means, and without a road network comparable to that of the great continental civilizations.

The problem wasn't just the city's total weight. Every single element had to be extracted, moved, and placed. In the reconstruction model developed in the chapter, an average basalt block of about half a cubic meter would have weighed around 1.45 tons. To reach a total mass of 13 million tons, nearly nine million blocks would have been needed. Millions of elements would have to be quarried, transported through a tropical environment or by sea, and finally positioned precisely within the structures.

Some of the basalt used to build Nan Madol has been linked to the Sokehs area, located on the opposite side of Pohnpei from the city. According to the chapter, approximately 40% of the columnar basalt came from that area. The origin of the remaining material, however, is still unclear. This means that enormous quantities of stone must have been transported for kilometers before they could even be used on the construction site.

If we imagine that at least a significant portion of the transportation took place by water, the problem requires vessels capable of supporting enormous loads. The model proposed in the chapter envisions large multihulled vessels capable of simultaneously transporting several blocks weighing over a ton each. Maintaining a sufficiently rapid construction pace would have required dozens of teams working every day, hundreds of sailors and transporters, in addition to the men working in the quarries and laying the stones.

But the construction site would have required more than just physical strength. People were needed to build and repair the boats, produce the tools, organize the work shifts, supervise the quarries, distribute the food, and coordinate thousands of men. Added to these were farmers, fishermen, and all the others needed to support a population engaged in a monumental project. In the reconstruction model, the construction site could have involved between 3,000 and 3,500 people each day.

And perhaps this is the true mystery of Nan Madol. Not so much how a single block was raised, but what kind of society was capable of organizing all of it . A city of this size requires command, planning, knowledge of the territory, transportation capacity, resource management, and a political continuity strong enough to keep a gigantic project operational for many years.

When we view Nan Madol as a simple series of ruins scattered between sea and forest, we risk missing the site's true significance. The problem isn't merely archaeological. It's logistical. Millions of tons of stone don't shift randomly. Millions of blocks aren't quarried, transported, and positioned without an organizational structure capable of coordinating people, resources, and knowledge.

Who, in the middle of the Pacific, had the capacity to organize such an undertaking? To truly understand the significance of building Nan Madol, it's helpful to compare it to Egypt. The pyramids weren't built by random groups of men dragging stones across the desert. Behind the Great Pyramid lay a complex civilization: a centralized state, an administration capable of organizing thousands of workers, controlled quarries, transportation on the Nile, specialized craftsmen, food supplies, priests, technicians, and a political structure stable enough to sustain a monumental project for years.

When we look at the Great Pyramid of Cheops, in fact, we don't just see millions of tons of stone. We indirectly see everything that must have existed behind those stones: villages, cultivated fields, officials, warehouses, vessels, measurement systems, hierarchies, technical knowledge, and a society capable of producing enough food to support thousands of people who were not directly involved in agriculture. The pyramid is only the visible part of a much larger civilization.

For consistency, the same reasoning should be applied to Nan Madol. If millions of tons of basalt were indeed moved for its construction, we cannot imagine a small island community without a complex structure behind the site. There must have been a system capable of quarrying the stone, transporting it for kilometers, building and maintaining large vessels, coordinating hundreds or thousands of workers, feeding them, and organizing the construction site. And all of this in one of the most geographically challenging environments on the planet: in the middle of the Pacific Ocean.

In other words, Nan Madol doesn't just require good builders. It requires a civilization. A civilization with an economic network, a ruling class, nautical knowledge, planning skills, and likely stable connections with other islands. The monumental city we see today would therefore be merely the final product, the surviving monument, just as the pyramids are the visible remains of ancient Egypt.

But Nan Madol is built on a tiny island lost in the ocean, practically built in the middle of nowhere. If behind those walls existed a society organized enough to build a project of such magnitude, where have the other traces of that civilization gone? Where are its large settlements, its ports, its shipping routes, its production centers? Where are the structures necessary to support a population capable of building and maintaining a monumental city?

It's clear that much of that civilization must be underwater. In this sense, Nan Madol is one of the most important pieces of evidence that part of ancient civilizations must necessarily be underwater. We just need to start searching for them in an organized manner, without fear of finding something that challenges our understanding of human history.

You can learn more about this topic in the book: