Why Amazon built its workers a mini rain forest inside three domes in downtown Seattle

Microsoft employees have treehouses. Apple workers have what's been called a spaceship. And now Amazon.com's staffers have a rain forest — or at least something like one — right in the middle of downtown Seattle.

On a typically rainy and covercast Monday, in a particularly Amazonian version of a ribbon-cutting ceremony for the Spheres — its giant glass-and-metal domes filled with tropical and rare plants — CEO Jeffrey P. Bezos asked the gathered attendees to look to the ceiling. A circular blue ring lit up, and the Amazon founder summoned its artificial intelligence assistant, Alexa, to officially open the building. (Bezos is also the owner of The Washington Post.)

“Okay, Jeff,” Alexa's familiar voice sounded, as lights switched on and misters sprayed some of the more than 40,000 plants that stock the company's newest headquarters building. This architectural showstopper is a new Seattle landmark and Amazon workplace tool that could help the retail giant attract, retain and enhance the productivity and well-being of its fast-growing workforce.

After more than six years of planning and construction, the massive urban garden is now open for employees to hold meetings beside a cascading waterfall, brainstorm in a third-story "bird's nest” or crack open their laptops and work amid a lush array of ferns, tropical plants and a 50-foot ficus tree nicknamed "Rubi.” For now, Amazon employees will have to reserve a time slot to enter the building, but over time will be able to come and go from what executives call an "alternative workspace” that's aimed at boosting collaboration and creativity.