Biosphere 2

Biosphere 2 is a 3.14-acre (1.26-hectare) place of research in the United States.
It is a closed ecological system located in Oracle, Arizona. It was designed as a technological system to explore the complex web of interactions within a closed ecological system. The facility consists of five biomes—a tropical rainforest, an ocean with a coral reef, a grassland savanna, a fog desert, and a mangrove wetlands—each of which is an independent and self-sustaining ecosystem. The facility was built between 1987 and 1991 and was sealed from the outside environment and stocked with 3,800 species of plants and animals, including humans, and was intended to be a self-sustaining system for two years. After two years of operation, it was opened to the public in 1993. The experiment ended in 1994, but the facility remains open for research and educational uses. Biosphere 2 continues to be used to research the effects of climate change and other environmental issues, as well as to help build a better understanding of how closed ecological systems work and how they can be used to address global problems.