Greensburg Kansas, was devastated by a tornado on May 4th, 2007 with nearly 90% of the city destroyed. When the residents decided to rebuild their community, they made a conscious effort to make it the greenest in the country. "The timing of all this is, in some ways, almost spooky," Daniel Wallach, a nonprofit specialist helping Greensburg rebuild said. "It's like the world was ready for this to happen, for a town to be completely re-imagined. The tragedy was terrible. But the folks here know that it also provided an incredible opportunity." CNN video segment here.