Amazon’s three plant-filled spheres will open in its $4B downtown Seattle office Monday after seven years of planning and construction. The spheres are filled with 40,000 mature plants from around the world. 

Three years ago, Amazon CEO Jeff Bezos told the company horticulturist the vegetation should appear developed when the facility opened. He did not want saplings and seedlings in the spheres that would take five years to mature, Bloomberg reports.

“The question I got back was, ‘well, can we have year five on day one?’” Amazon horticulturist Ron Gagliardo told Bloomberg. “And that’s kind of been our motto ever since.”

The mature foliage includes a 55-foot-tall Ficus rubiginosa tree, affectionately named Rubi, which was transported from Southern California. It was hoisted into the sphere by a crane and dropped through a hole in the roof last summer.

The three glass-and-steel spheres contain warm, moist air that is about 72 degrees and 60% humidity. The biggest sphere is 90 feet high and 30 feet wide. The climate varies, allowing visitors to find comfortable micro-climates. The temperatures vary by five degrees. There is a drastic difference in the humidity levels. Ventilation systems provide a simulated breeze.

A five-story living wall features cascading greenery.

There is WiFi, and there are meeting spaces, such as the bird’s nest perched along a suspension bridge.

The spheres can accommodate 800 people at a time and will serve as an employee getaway, but employee badges will record how long each worker spends there. 

The project created 600 full-time jobs from design through construction, according to Bloomberg.

CORRECTION, FEB. 2, 6:25 P.M. PT: A previous version of this story did not reflect that Amazon has invested $4B in its entire urban campus, of which the spheres are a part. The story has been updated.