Mega Structures of the World

Mega structures and Architectures
Mega constructions of the World
In science fiction and speculative (or exploratory) engineering, a mega structure is an enormous self-supporting artificial construct. The definition is often informal and varies from source to source, but generally requires at least one dimension to be in the hundreds of kilometers. Other criteria such as rigidity or contiguousness are sometimes also applied, so large clusters of associated smaller structures may or may not qualify. The products of megascale engineering or astroengineering are megastructures.
Megastructures are also an architectural concept popularized in the 1960s where a city could be encased in a single building, or a relatively small number of buildings interconnected together.
Megastructures often play a part in the plot or setting of science fiction movies and books.