Chinese designers entered a skyscraper design contest sponsored by eVolo. The contest was seeking green, environmentally friendly construction in the desert. The Chinese designers came up with a network of buildings constructed with the help of large 3d printers which used sand as their building material, called the Sand Babel Towers.

http://3dprint.com/1765/sand-babel-s...ers-with-sand/

Although this is only a concept for now, such a design could one day be seen constructed, with the help of larger scale 3d printing technology. Chec out what the designers envisions the Sand Babel towers looking like: