Biosphere 2 is a large-scale ecological research facility located in Arizona, designed to study Earth's ecosystems. It was built between 1987 and 1991 and is named "Biosphere 2" because it serves as a model for understanding the Earth's biosphere, which is the global sum of all ecosystems. The facility includes various biomes, such as rainforests, deserts, and oceans, all contained within a glass and steel structure. Researchers use Biosphere 2 to explore the interactions between different ecosystems and to study the effects of climate change, making it a valuable tool for environmental science.