Workers broke ground recently in Seattle on a six-story building that will generate its own power, collect and reuse rainwater, compost its sewage, and depend on daylight instead of halogen lamps. Its owner, the Bullitt Foundation, which supports work in sustainability, set out to build the greenest building on Earth. We'd say they're earning that title.

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Other green features: The building is being made with sustainably harvested wood and will not contain contaminants like lead or mercury. Occupants will also be able to open the windows and tenants will be required to use technology that automatically turns off when idle.

All of this comes at a price. The building will cost $30 million, about a third higher than for conventional construction, and the foundation has to pay much of that cost out of pocket since the bank is a little leery of the whole thing. But Bullitt intends for the building to last 250 years. So in theory, doling out a little more green now will pay off later.

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