7 most expensive megaprojects in human history

Human civilization has a strange habit: no sooner do we learn to build something big than we almost immediately try to build something even bigger. A pyramid the height of a skyscraper. A wall spanning half a continent. A canal between seas. A station the size of a football field—only this time in space. Sometimes this is driven by practical calculations, sometimes by politics, prestige, or an almost mad belief in one's own abilities. But every such project has yet another dimension. The price tag.

Things are complicated when it comes to ancient construction projects: the Egyptians did not leave us invoices from limestone suppliers. Therefore, historians and economists count working days, volumes of materials, logistics, feeding the builders, and try to convert all of this into the currency of today. It is easier with projects of the 20th and 21st centuries—they already have budgets, reports, and very real billions.

The comparison still turns out to be a bit bold. And perhaps that is precisely what makes it interesting.

1. The Great Pyramids of Giza — Billions That Didn't Exist Yet

The Pyramid of Khufu looks almost defiant even after several millennia. Originally, it rose to about 146 meters, and its mass is estimated at roughly six million tons. For a society without excavators, cranes, trucks, and railroads, this sounds like a technical joke. Yet the structure still stands.

The pyramid, of course, has no direct price. Money in the form we are familiar with was not involved in construction at all back then. Therefore, researchers attempt to estimate the cost through the number of workers, their maintenance, food production, the construction of workshops and housing, stone quarrying, and its delivery.

But there is a catch. If you were to decide today to repeat the project and fundamentally abandon modern technology while keeping current labor pay and safety standards, the total could easily fly well past a trillion dollars. Stone would not turn out to be the most expensive part. The most expensive part would be human labor—or more precisely, millions of hours of it.

2. The Great Wall of China — An Invoice Spanning Two Thousand Years

The Wall is even more complicated. We are used to thinking of it as a single giant object, when in reality it is a system of fortifications that was built, rebuilt, connected, and abandoned by different dynasties.

The first large-scale fortifications appeared B.C., and the latest major sections date back to the Ming era. This amounts to construction on an almost civilizational scale—not twenty years, not fifty, but a massive historical span.

If we count primarily the materials and imagine the use of modern machinery, estimates could start at roughly $200 billion. But if you try to include the manual labor of millions of people over the centuries, the calculations turn into tens of trillions.

How accurate is such a sum? Frankly, not very. But it does a great job of conveying a sense of scale. The Great Wall of China is a case where the usual question "how much did it cost?" almost stops working.

3. The Suez Canal — 193 Kilometers That Changed the Trade Map

The Suez Canal can be approached with much greater confidence. Construction took place from 1859 to 1869 under the leadership of Ferdinand de Lesseps. After opening, ships gained a short path between Europe and Asia instead of the long detour around Africa.

Distances on some routes were shortened by approximately eight thousand kilometers. In other words, what we have here is not just a trench dug in the sand, but infrastructure that literally redrew the movement of goods between parts of the world.

After attempting to account for purchasing power, gold, and inflation, the estimated figures come out to around $15–20 billion in today's money. For an object of such significance, the sum even seems modest.

4. The U.S. Interstate Highway System — A Megaproject Hiding Beneath Wheels

Some giant projects can be seen from afar. Others grow so densely into everyday life that people stop noticing their scale.

In 1956, under President Dwight D. Eisenhower, the United States began building the Interstate Highway System. The result—tens of thousands of kilometers of roads connecting the country's largest cities.

These highways changed more than just driving routes. Suburbs grew faster, businesses gained new logistical capabilities, and the personal car finally transformed into an everyday tool for millions of Americans.

A curious detail: the interstate highways make up only a small fraction of the entire U.S. road network, yet they handle a huge share of vehicular traffic. The massive construction project ultimately became so familiar that its grandeur nearly vanished from sight.

5. The International Space Station — Construction Where You Can't Call a Regular Crane

The ISS breaks the rules by its very location. Most megaprojects suffer from complex material delivery logistics. Here, literally every kilogram first had to be lifted from the Earth's surface.

The first module of the station—Zarya—was launched in 1998. Then new compartments, trusses, solar panels, laboratories, and equipment were sent into orbit. Dozens of missions were required for assembly.

People have been continuously on board the station since November 2000. Fifteen countries participated in the project, and general expense estimates usually range from $100 to $200 billion.

The spread is understandable. What should be counted as the cost of the ISS? Only the manufacturing of the modules? Their development? Shuttle launches? Ground control centers? Cargo delivery? Maintaining the station in working order?

Add just a couple more expense lines—and the table starts expanding before your eyes.

6. The Three Gorges Dam — A Structure That Even Affected Earth's Rotation

China's Three Gorges Dam looks as though someone decided to test just how far one can go in managing the natural landscape.

Construction began in 1994. Main works were completed in 2006. The dam stretches for more than two kilometers and reaches roughly 185 meters in height.

Official construction costs were about 180 billion yuan. But the matter was not limited to a single concrete wall. The project required the resettlement of a huge number of people, the construction of new roads, the relocation of infrastructure, and environmental measures.

There is also an almost fantastic detail: the redistribution of a massive amount of water slightly altered the Earth's moment of inertia. As a result, the length of the day may have increased by about 0.06 microseconds.

This is completely imperceptible to a human. But the very thought is wonderful: we built a dam so massive that the effect had to be discussed at the level of planetary rotation.

7. NEOM — An Attempt to Buy a Piece of the Future

And finally, a project whose price tag exists predominantly in the future tense.

NEOM in Saudi Arabia is not a single building or even a single city. It is a vast territory with multiple projects, among which The Line has received the most attention—a conceived linear city stretching up to 170 kilometers.

The idea almost deliberately looks like a science fiction concept: to build a new urban environment from scratch in the middle of a desert region, making it technological, compact, and largely autonomous.

Initially, a figure around $500 billion was mentioned in connection with NEOM. But the final cost of such a project is currently impossible to name. The more infrastructure, energy, transport, and urban environment that has to be created from scratch, the faster the bill grows.

The territory of NEOM is stated to be approximately 26,500 square kilometers. This is no longer just a construction site. Rather, it is an attempt to create a separate economic and technological region.

Will it turn out to be the exact futuristic city shown in the concepts? Here I would not rush to place bets. Megaprojects love to change their shape, timelines, and budgets along the way.

So Which Megaproject Is the Most Expensive?

If you look only at actual expenses in familiar currency, the leaders will include the American highway system, the International Space Station, and potentially NEOM—if the stated plans are implemented on a full scale.

But with ancient structures, a different arithmetic comes into play. The Great Pyramid or the Great Wall of China were built in societies where the cost of human labor, the economic system, and the very idea of a budget were completely different.

Therefore, the main takeaway here is not even about money.

Behind the pyramid stand tens of workers. Behind the Wall—generations. Behind the Suez Canal—ten years of digging earth between two seas. Behind the ISS—rockets, engineers, and assembling a structure at an altitude of about four hundred kilometers overhead.

Billions help compare scales. But the greatness of these structures is born elsewhere—where a single human idea turns out to be so powerful that people begin moving stones, rivers, mountains, and sometimes even the boundaries of the possible for its sake.