SunHawk is an off-the-grid private home designed by architect Craig Henritzy that functions like a living organism, running entirely on renewable solar and hydroelectric energy.

The California Academy of Sciences in San Francisco has a 2.5 acre living roof upon which some 1.7 million native plants grow.

Rising out of the flatlands of Central California, the earth-sheltered home at Eatwell Farm provides a cool sanctuary on hot days.

Earth-sheltered homes are among the most energy-efficient architectural designs. They can save as much as 90 percent of heating and cooling costs compared to traditional homes.

On the roof, a meadow of wild grasses and flowers have taken root, spilling over the concrete edges. The roof is strong; visitors can walk right to the top.

The EcoCenter at Heron's Head Park is a green oasis in a heavily industrialized area on San Francisco's southern waterfront. The off-grid building serves as a venue for environmental justice education.

The EcoCenter is one of the most water efficient buildings in the world. A sophisticated treatment and recycling system uses a series of wetland "cells" to filter and purify wastewater, which is then used for landscape irrigation.

The EcoCenter's green roof provides habitat for local pollinators and captures rainwater, which is then filtered through the artificial wetland.

A wood and rope bridge provides access to a one-of-a-kind treehouse located in Northern California's Santa Cruz Mountains.

Supported by three large redwoods, the treehouse is elevated over the forest floor.

A redwood tree trunk occupies the living and sleeping area.

The treehouse design is built around nature.

The vertical garden at San Francisco's Drew School contains dense vegetation pouring from its facade.

The living wall is the largest North American installation by French botanist Patrick Blanc. More than 4,000 plants were stapled into a cloth membrane, which is watered by a built-in irrigation system.

One hundred different native plant species grow on the Drew School.

The Harbin Hot Springs Temple, by architect SunRay Kelley, showcases multiple natural building techniques. The round shape is modeled after traditional nomadic structures, like a yurt or ger.

Spiraling purlins meet at a skylight beneath a large, glass encased cupola.

The main structure is formed by cob, an ancient building material consisting of clay, sand, straw, water and earth that can be formed into a variety of shapes.

Patrick Dougherty's organic sculpture at the Bay Area Discovery Museum in Sausalito blends into the surrounding foliage.

The structure is built with thousands of tree saplings that create a labyrinth for visitors to explore.

Using the same techniques that a bird would use to build a nest, Dougherty wove sticks together to create unexpected forms.

Like all of Dougherty's works, the sculpture is temporary and it will be removed once it starts falling apart in two to three years.