This story may be a day late for Earth Day, but it is inspiring nonetheless: U.K. insurance company CIS has perhaps the greenest skyscraper in the world. Its corporate headquarters in Manchester, England is a model of environmentally friendly building design. The original building was covered with mosaic tiles that eventually cracked and fell off, so in the process of redesigning the building, the company's executives decided to contract SolarCentury, a green building company, to panel the façade of the building in 7,244 80-watt solar panels. Of the total number of panels on the building, just under 5,000 are active, and they currently generate about 390 kilowatts of electricity. As the rest of the panels go online, the company hopes to generate even more power.

To add to the wattage that the building generates, 24 wind turbines on the roof of the building generate approximately 10 percent of the building's overall power. The project was expensive, as green projects usually are, but over time the company hopes to generate enough electricity not only to make the building self-sufficient, but also to sell excess power back to the power company for distribution to other customers. [ via NewLaunches ]