In the 1990s, the Americans tried to build a miniature artificial ecological system in the desert north of Tucson, Arizona. Its purpose was to conduct ecological and environmental research in a closed environment as well as to help humans understand how Earth operates by simulating its ecological environment.
This plan was originally proposed by a rugby player and received investments from several consortiums, including Rockefeller, totaling US$150 million. It was quite a commotion at that time.
Unfortunately, the final experiment results weren't as sensational as the proposal. A year after the experimental team started their work at the Biosphere 2, they declared the project a failure. They had to withdraw from the project.
The only conclusion drawn from the experiment was that Earth might be the only suitable planet for humans.
