The public toilet: The last choice for anyone who really needs to go, and with good reason. When the door's closed, any number of unhealthy or illegal activities could be going on in there, inevitably leading to damage, or at least a big mess. The city of Lausanne, Switzerland might have the perfect high-tech solution to this urban blight, however: a public head with transparent walls.

Before you file this in the "stupidest idea ever" folder, you should know the walls can turn opaque at the push of button. The glass sides are partly made of liquid crystal, so when the occupant hits the button they come under electric tension, going dark and ensuring privacy. There's a motion detector that'll make the glass clear again if there's no movement — or if there's, ahem, too much (American Pie sequel writers, take note).

We like the idea, though considering the toilet's high cost, it might not be the best for some cities. New York is probably a wash — the glass would probably get broken too quickly. Where do you think is the best place for it? I vote for Winnipeg (just because it doesn't get voted for often enough).