The Arizona Desert Holds a 3-Acre World With Rainforest, Ocean, and Savanna All Under One Roof

Biosphere 2, Arizona

Tucked in Oracle, Arizona, Biosphere 2 isn’t your average science experiment. In 1991, eight researchers sealed themselves inside this massive glass structure to prove humans could survive in space.

While that didn’t quite work out, the 3.14-acre facility is now the world’s largest Earth science lab, studying everything from climate change to coral reefs. Best of all, you can visit it today.

Massive Rubber Lungs Help This Building Breathe

This sealed glass building has two giant “lungs” hidden in geodesic domes. They shift up to 16 feet daily to keep air pressure balanced so the glass doesn’t break.

These 40,000-pound systems use huge aluminum dishes connected to rubber membranes that move up and down as temperatures change.

During your tour, you can visit one lung and even push against the weighted plate. The rubber is so tough it has lasted decades without needing replacement.

The Hidden Underground City Most Visitors Never See

What you see above ground is just half the story. Underneath Biosphere 2 features the “technosphere,” a massive basement covering the entire 3.14-acre footprint.

This hidden world contains all the behind-the-scenes equipment: 26 air handlers that manage temperature, create rain, and control humidity.

Staff members once rode bicycles through this underground maze just to get around. It has over 7 miles of pipes, 1.5 miles of tunnels, and complex water filtration systems.

Uninvited Roaches Took Over Despite Careful Planning

Researchers planned to bring in four cockroach species to help recycle organic matter. But common household roaches sneaked in and thrived, in some areas, thousands of roaches occupied every square meter.

Tramp ants also invaded and quickly became the dominant ant species. Researchers had to develop special trapping methods that pest control experts still use today.

A Million-Gallon Ocean Sits in the Arizona Desert

You might be surprised to find an ocean in the Arizona desert. This ocean needs 26 different pump systems to keep water circulating properly.

The Marine Mesocosm spans 35×20 meters, holds 2.6 million liters of water, and reaches depths of 7 meters. The custom wave machine creates realistic tides and a beach area where waves naturally break against the shore.

Today, you’ll see researchers using this controlled environment to study how to protect endangered coral reefs.

Making a Single Pizza Took an Entire Growing Season

For Biospherians, making pizza meant growing wheat for four months, then waiting for tomatoes, peppers, and onions to ripen.

They grew 80% of their food on just half an acre, producing over 6,000 pounds of food yearly. Their farming methods actually yielded more calories per square foot than conventional agriculture.

During your tour, you can still see banana, papaya, and coffee plants descended from their original agricultural system.

How Thousands of Plants From Four Countries Built a Rainforest

The rainforest area started with variety: About 2,800 individual plants from more than 400 species were collected from Puerto Rico, Belize, Venezuela, and Brazil.

The rainforest canopy now grows 90 feet tall, touching the glass ceiling. You can find special “misting benches” that create conditions like those in cloud forests.

The trees grew three times faster than expected because they had perfect growing conditions and no wind to slow them down.

Hungry Soil Bacteria Almost Suffocated the Crew

One of the biggest challenges was unexpected oxygen loss. Soil bacteria consumed oxygen much faster than anyone predicted.

The soil contained too much organic matter, creating ideal conditions for bacteria to multiply. Oxygen levels fell from 20.9% to just 14.2% within 17 months. This problem actually helped research on managing life support systems for space habitats.

Today, the facility uses advanced monitoring systems that can detect tiny changes in oxygen levels, and researchers have introduced specially managed soil microbial communities since 2018.

Why Twenty Minutes Without Power Would Destroy Everything

The Arizona heat makes power reliability critical at Biosphere 2. If the cooling systems failed on a hot day, the ecosystems would suffer permanent damage within 20 minutes. To prevent this, you’ll see backup power systems like natural gas generators, diesel backups, and a dedicated electrical substation.

Throughout the facility, you’ll notice emergency instructions explaining what staff should do if different systems fail. The temperature control system processes over 5,000 measurements every minute.

The Complete Coral Reef Hidden Under Glass

During the original two-year mission, the ocean contained a complete living coral reef, including 40 different species brought from the Florida Keys and the Caribbean.

You can watch researchers develop techniques to restore endangered coral reefs. Fourteen automated sensors constantly monitor water chemistry.

The facility even recreates coral spawning events monthly using special lighting that mimics the moon’s cycles, helping scientists grow new reef-building species.

The Desert That Floats on Its Own Foundation

The desert section sits on a 500-ton welded structure that essentially allows it to “float” separate from other areas. This design keeps moisture from seeping in from adjacent biomes.

The desert sphere further demonstrates fog-harvesting technology that shows how coastal desert plants collect moisture from the air. When you walk through, you’ll see 13 different cactus and succulent species that wouldn’t naturally occur together in the wild.

Plan Your Visit to Biosphere 2

Address: 32540 S. Biosphere Road in Oracle, Arizona

This unique research facility works best for visitors ages 8 and up who are interested in science and the environment. You can call them at 520-621-4800 with questions.

No outside food is allowed inside, but you can grab snacks at the gift shop. For a proper meal, you’ll need to drive about 15-30 minutes to nearby restaurants. The closest option is The Oracle Patio Cafe, just 5.2 miles away.

Hours and Admission

• Open daily from 9 AM to 4 PM (except Thanksgiving and Christmas).
• Tickets cost $29 for adults, $27 for seniors, and $15 for children ages 5-17.

Your self-guided tour takes about 75 minutes using the facility’s app. Remember to download it before arriving for the best experience.