When Candida Figueiredo and her husband Jorge Varela aka Oitoemponto first moved into their house in Vizela, Portugal, she had a few sleepless nights. "The first few days, I thought, 'My God! My bedroom is just hanging in mid-air. There is nothing to support it!" Made of a single block of reinforced concrete, and nailed in place using techniques more commonly used in bridge construction.