Urine Diverting Dry Toilets, or UDDTs, are toilets that can function without water. Amazingly enough, these toilets also prevent unsanitary conditions or bad smells.  The toilet accomplishes this by separating and drying the urine and feces, which reduces the smell commonly associated with human waste. If built with a recovery method, the waste collected in these toilets can also easily be used as fertilizer for farms. (Toilet pictured to the left is from Tamil Nadu, India)