Biosphere 2

Biosphere 2 was conceived in the 1980s as a bold private venture, an attempt to build a fully sealed, self-contained world that could sustain human life without any exchange of air or materials with the outside. Inside, the crew would grow their own food, and the plants, soil, water, and air would cycle in a closed loop, just as they do on Earth. The goal was to learn how such systems work and whether people might one day live this way on other worlds.

In the early 1990s the first crew of eight sealed themselves inside for two years. The experiment proved far harder than anyone expected. Oxygen levels fell and had to be adjusted, crops struggled, and the closed world threw up surprise after surprise. A second, shorter mission followed. The missions did not achieve every goal, but they yielded a wealth of knowledge about how tightly coupled and fragile Earth's living systems really are.

What makes a visit so memorable is stepping into the biomes themselves. Under the great glass panes are re-created ecosystems, each with its own climate and life. The rainforest is warm and humid, dense with tropical plants; the ocean holds a small coral reef with actual seawater; a mangrove marsh, a savanna, and a fog desert each recreate their own corner of the natural world.

Beneath and around these worlds runs an extraordinary web of machinery. Great chambers called the lungs allow the sealed air to expand and contract with temperature so the glass does not burst, and pumps, pipes, and systems circulate water and air. Touring the technical spaces below the biomes is as fascinating as the biomes above, revealing just how much engineering it takes to keep an artificial world running.

After the original missions ended, Biosphere 2 found new purpose as a research facility, now operated by a major university. Rather than sealing people inside, scientists use the controlled environments to study how ecosystems respond to change. Because they can adjust temperature, rainfall, and carbon dioxide inside the biomes, researchers can run experiments on climate and ecology that would be impossible in the open world.

One landmark project fills a hillside inside the glass with soil and instruments to study how water moves through landscapes, from rainfall through soil to plants and streams. Visitors touring the facility often see this real science underway, which turns a visit into more than a look at a famous relic. It is a working laboratory probing questions about the future of the planet.

Biosphere 2 sits in the high desert north of Tucson, in the foothills of the Santa Catalina Mountains near the small community of Oracle. The location was chosen partly for its clear skies and stable climate, and the setting is striking, a futuristic complex of white domes and glass pyramids rising from the rolling desert with mountains behind.

The surrounding country is classic southern Arizona high desert, all grassland, oak, and cactus, cooler and greener than the low desert around Tucson. Nearby Oracle and the Catalina foothills offer their own quiet attractions, and the great Santa Catalina range, crowned by Mount Lemmon, rises just to the south. Against that backdrop, the gleaming glass ark of Biosphere 2 looks like something set down from another century.

The closest Boutel™ stays, so you can turn this stop into an overnight. Each is an independently owned, editorially selected place to stay.