"Mega Projects" is an older term that is no longer considered politically correct. The name was applied to very large capital projects, such as those in oil-sand refineries. The "Mega" applies to the money... millions of dollars (which soon became billions).
One such "mega project" was the James Bay Project. This project was in hydroelectric-power development: "In 2 phases a total of 8 generating stations were constructed to produce more than half of Québec's hydroelectric power."
The recession of the 1970s put an end to the massive projects; they required security to continue on such enormous scales.