What are they? Giant spheres bubbling up in Denny Triangle

SEATTLE — The giant spheres in Seattle' Denny Triangle might be less of a mystery than Amazon's reported clothing line, but the large-scale project is definitely turning heads.

Currently just skeletons of their future selves, the buildings will become three ornate glass spheres in Amazon's growing Seattle campus.

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Once finished, the buildings will create an "alternative environment," where employees can work and socialize in a park-like setting.

"The generative idea is that a plant-rich environment has many positive qualities that are not often found in a typical office setting," according to design documents.

"While the form of the building will be visually reminiscent of a greenhouse or conservatory, plant material will be selected for its ability to co-exist in a microclimate that also suits people," the documents continue. "To encourage growth and maintain the health of the plants, the building's interior will include high bay spaces on five floors totaling approximately 65,000 SF and capable of accommodating mature trees."

Already a stark contrast to the skyscrapers surrounding them in the three blocks near WestLake Avenue, the spheres are sure to become yet another recognizable landmark in a booming city.

The largest of the three spheres will be 95 feet tall and 130 feet in diameter – equivalent of an eight-story building. They are part of a 3.3 million-square-foot office and retail complex.

Plans call for the glass spheres to house about 300 plants from more than 30 countries. Amazon will employ a full-time horticulturist to tend to the plants.

Architects at NBBJ compare the project to similar glass biosphere projects in Arizona, Montreal, Genoa, Italy, and the Royal Greenhouses in Belgium.

The project is expected to be complete in 2017.

Cox Media Group