G5K

G5K (short for Galaxy 5,000), pejoratively referred to as The Un-Mountain, is a visionary arcology and megatall skyscraper located on the partially-finished Strangereal Island off the coast of Port Byron, Patagonia, proposed by architectural firm W.R. and Sons., Pte. Ltd. in 1991 as part of the Patagonian Bicentennial celebrations.

Originally, the G5K was meant to be the sole structure on the island, however the project was scrapped and passed off as a fantasy after realizing the cost of the project and the potential risk of damage it might face.

If it was indeed built, it would become the world's tallest man-made structure, succeeding the Ultima Tower in San Francisco, United States, and X-Seed 4000 in Tokyo, Japan, being beaten only by the Tokyo Tower of Babel at 10,000 meters. The building's design is inspired by Mt. Fitzroy and takes influences from Japanese cyberpunk (mostly sci-fi anime).

Design rights handover
In 2020, the rights to the building's design were awarded to Patagonian video game music band Power Up!, which later used the building's design as a backdrop in their videos. This is the second visionary supertall structure in Patagonia to have its design rights given to someone else, the other being the Columbia Vertical City which was given to Port Desire-based Andrew Evans.