Amazon wants its new downtown Seattle campus to be green and sustainable, and one part of that is capturing and retaining one of the more abundant resources in the Pacific Northwest, rain.

On the first block of this campus, which opened last year, Amazon teamed up with Columbia Green Technologies of Portland to build green rooftops on both the Doppler office tower and adjacent Meeting Center. The roof manages stormwater, retaining water that would otherwise flow into the city’s stormwater system.

“We have the opportunity to do things right,” Amazon Director of Global Real Estate & Facilities John Schoettler said in a press release. “Our urban campus is part of the broader city scape and provides our employees with all of the urban amenities they would want. We also focused to ensure the environment we created is sustainable, a place employees will feel good about working in. These new green roof buildings help us do that.”

Sustainability, fiscal considerations and efficiencies all played a role in Amazon’s decision to build green rooftops with Columbia Green, according to a press release.

“Green roofing has grown tremendously in the last few years because building owners are realizing the benefits of utilizing green roofs on empty space instead of having a retention tank,” Columbia Green CEO Vanessa Keitges said in a statement. “Especially in an area where it rains a lot, this makes sense. More companies are also changing their building environments to make healthier places for people to live and work – greenery and green roofs are part of this.”

The smaller building on the block, the Meeting Center, contains a large amphitheater with a stage, fold-up stadium seating and basketball hoops that can be lowered from the ceiling. It’s connected by a covered awning to Doppler, a more traditional 36-story office tower that sits next door.

The second office building on the campus — which shares the block with a triumvirate of mystical spheres — is set to open in November. Amazon owns two other blocks in the neighborhood that it could develop. Today, Amazon occupies 34 buildings and approximately 8.5 million square feet in Seattle and could grow up to 12 million square feet across 40 buildings by 2022.