Measuring just five feet at its widest point, the ultra-thin home was unveiled in the Polish capital of Warsaw on Sunday, October 21, 2012. Photo: The Keret House is squeezed into the space between two apartment buildings in Warsaw. There's a four-inch gap between the apartment buildings to either side. A perforated steel facade was used to allow in more light. (Photo by Andrea Meichsner/The New York Times)

Construction cranes stand on the Unstrut Valley high-speed railway bridge on March 19, 2012 near Karsdorf, Germany. The Unstrut bridge, which is 2,668m long (about 1.6 miles), is among 38 bridges and 26 tunnels German state rail carrier Deutsche Bahn is building along a new ICE high-speed railroad connection between Nuremberg, Erfurt, Halle, Leipzig and Berlin in a multi-billion Euro project across eastern Germany called the German Unity Transportation Project (Verkehrsprojekt der Deutschen Einheit). (Photo by Sean Gallup/Getty Images)

Melanie Baier from the village Obergurig wearing a traditional Lusatian sorbian folk dress, paints an Easter egg in traditional Sorbian motives at the annual Easter egg market on March 24, 2012 in Schleife, near Hoyerswerda, Germany. Easter egg painting is a strong part of Sorbian tradition and visual elements within the painting are meant to ward off evil. (Photo by Carsten Koall/Getty Images)

Wellcome trust employee Zoe Middleton poses behind an artwork entitled “My Soul” by Katharine Dowson, which consists of a laser etched lead chrystal glass formation in the shape of a brain, and was created using the artists own MRI Scan, at Wellcome Collection on March 27, 2012 in London, England. (Photo by Dan Kitwood/Getty Images)

Activists protesting cuts in subsidies to solar power in Germany protest outside the building where Vice Chancellor and Economy Minister Philipp Roesler and Environment Minister Norbert Roettgen were announcing the cuts on February 23, 2012 in Berlin, Germany. (Photo by Sean Gallup/Getty Images)

Hostesses pose for photos with a police officer on the motorized vehicle during the third plenary meeting of the 11th National Committee of the Chinese People's Political Consultative Conference (CPPCC) at The Great Hall Of The People on March 10, 2012 in Beijing, China. (Photo by Feng Li/Getty Images)

Father Juan Manuel Villar blesses a dog during the feast of San Anton, the patron saint of animals, at the San Anton church on January 17, 2012 in the center of Madrid, Spain. San Anton is honored by many Catholic churches in Spain where thousands of animal lovers flock to their nearest place of worship to have their animals blessed. (Photo by Jasper Juinen/Getty Images)

The #8 DP Starworks Motorsports Ford Rley driven by Enzo Potolicchio, Ryan Dalziel, Alex Popow, Lucas Luhr and Allan McNish runs off the track during the Rolex 24 at Daytona International Speedway on January 28, 2012 in Daytona Beach, Florida. (Photo by John Harrelson/Getty Images)