This is the list of megaprojects, i.e. highly invested and large-scale projects. They are also sometimes called “megaprograms”. Some of these projects are so large that the list may never be complete. The most expensive project in world history in terms of inflation-adjusted monetary cost is the U.S. highway system.
Projects that cost more than US$1 billion and attract public attention due to their significant impact on communities, the natural environment, and budgets.