Take one beach, one sand binding agent, one laptop and one Super Sand Robot 3D printer and what do you get? How about a full-size building capable of containing numerous people?
Well, it's not quite at that stage yet, but a group of enterprising students at Catalonia's Institute for Advanced Architecture have created a system wherein the aforementioned Super Sand Robot is capable of building scale models of architectural designs out of nothing but sand, sun (it's solar powered) and a bit of LEED accredited binder. It's in 'house for ants' territory at the moment, but give it a few years and we could be giving the phrase sand castle a very literal definition.
Scroll down for a vid demo.