From: http://mars.nasa.gov/allaboutmars/facts/#detailedFacts

Makerbot ran a great contest to 3D print a home on Mars.   In cooperation with NASA’s Jet Propulsion Laboratory, contestants were challenged to create a mars base that could deal with the harsh conditions, dust storms, lack of oxygen and radiation found on the red plant.  Here are some fun Mars facts to give an idea of the challenges.  There were some great entries borrowing from nature with honeycomb to borrowing from the ancient engineering with a pyramid.  Head on over and check it out!