This episode is set at the Macallen Building, Boston's first LEED-certified condominium building and a large-scale example of sustainable design. In Knoxville, Tenn., host Kevin O'Connor visits ZEBRAlliance, a four-house joint project between a private developer and the Oak Ridge National Laboratory to determine the most cost-effective way to build a super-efficient house. At the International Builders' Show in Las Vegas, Nev., licensed contractor and host Amy Matthews sees how pervious pavement lets rain run-off into soil where nature intends it to. Kevin explains the features of wood certified by the Forest Stewardship Council. Amy talks to world-renowned architect Thom Mayne about the floating house he's designed for use in New Orleans, La., and anywhere else rising waters are a problem.