Megaproject

Itaipu Dam in South America, an example of a 20th-century megaproject
The Trans-Siberian Railway and other railways in the Asiatic part of the Russian Empire were important 19th-century megaprojects.

A megaproject is an extremely large-scale investment project. They can be defined as "temporary endeavours (i.e. projects) characterised by: large investment commitment, vast complexity (especially in organisational terms), and long-lasting impact on the economy, the environment, and society". Megaprojects may refer to construction projects but also decommissioning projects with multi-billion budgets, and a high level of innovation and complexity, affected by a number of techno-socio-economic and organizational challenges.