Most technology companies seem to set up shop in “hip” cities like San Francisco or New York — places they can find an eager young workforce. Amazon has taken a different approach, preferring to remain in its home city of Seattle and build up. The online retailer has expanded repeatedly, and now occupies more than 15% of the city’s office space. That’s fine, but Amazon wants more than traditional offices. Part of the company’s new Seventh Avenue expansion includes three giant biospheres that Amazon considers the workplace of the future.These biospheres are currently under construction, expected to be open to employees in 2018. The metal frames were completed earlier this year, and construction crews just recently started fitting all the triangular glass panes that make up the spheres’ faceted surfaces. Each sphere is 100-feet tall and will feature walking paths, casual work spaces, and meeting rooms suspended in the trees. Amazon’s management hopes employees will spend more time on campus in the biospheres (and maybe get more work done).What it’s supposed to look like when it’s done.Amazon wants to have around 300 different plant species growing inside the domes when they’re complete, and these won’t all be native to the Pacific Northwest. Amazon has a staff horticulturist whose job it is to find plants from all over the world that will thrive in the cool, dry environment of the biospheres. Some of these will likely be endangered species, so this is a little conservation project in addition to a green office park.Amazon’s new offices won’t only be of the futuristic biosphere variety. The company is also building three large office buildings flanking the biospheres, which should open around the same time.