Megastructure refers to a massive man-made structure that is typically associated with science fiction. Some synonyms of megastructure include superstructure, megaproject, monumental architecture, massive construction, and large-scale engineering. Another synonym for megastructure is megalithic structure, which is used to describe large stones used in ancient structures such as Stonehenge. Some other related terms include futurism, which refers to artistic and cultural movements that explore technological and societal advancements. Additionally, the term "sublime architecture" can describe impressive man-made structures that evoke a sense of awe and amazement. These synonyms and related terms help to convey the impressive scale and futuristic nature of megastructures.