Ever wanted to pee off the side of a building on to innocent bystanders below? Well you still can't at Felix, a trendy bar and restaurant in Hong Kong, but it comes close.

The urinals overlook the bright cityscape below. But the story of this restroom is that once, there were no urinals. Just glass. Patrons to this restaurant urinated on the glass. Sensors on the glass detected the urination and flushed water down the side of the glass to clean it.