Photos: Green tech giants

Whimsical remnants from the days when Google's campus belonged to SGI. Google opened up the space, turning multiple stories into a loft-like environment.

Google's Building 43 is light and airy, featuring natural wood and recyclable carpet.

Building 43 on Google's campus is a testament to Earth- and human-friendly characteristics. Exposed air ducts illustrate the company's function-over-form philosophy.

Google's Building 43 features a prototype tent office.

Electric scooters and bicycles make Google headquarters look more like a university campus than an office complex.

Allowing Google employees to bring their dogs to work makes for a healthy, happy environment, say Googlers.

Free, wireless-Internet-equipped shuttle buses take Google workers from San Francisco and other cities to Mountain View.

An Olympic-size array of solar panels on the roof of Microsoft's Mountain View, Calif., campus.

Office and hallway floors at Microsoft's campus in Mountain View are covered with carpet made from recycled materials.

An outdoor water fountain sculpture at Microsoft's Mountain View campus.

Open area at Microsoft's campus in Mountain View.

A free shuttle transports Microsoft workers in Mountain View.