Amazon's latest construction in the Denny Triangle opened January 2018 and is quite different to the Amazon Tower I, which went up in 2015 down the street. Relatively low to the ground with the aesthetic of a sci-fi movie, the name says it all with the Spheres, which are constructed in white metals and glass and contain within them a veritable botanic garden's worth of plants.
You can stop in the atrium (called the 'Understory') for a small exhibit on the building's architecture and ethos. Tours are available as part of a larger tour of Amazon HQ, which can be arranged on the website.