Every advertising has an absolutely clear goal: to attract attention of potential clients. And this is a main task for every designer at advertising campaign planning. Doesn't matter: is it a Print-design, billboards or a movie for TV: the viewer is tide after daily bare information and he wants entertainment. 

One advertisement agensy  made this billboard has installed on many German cities.

From one hand they became for this work a big portion of heavy criticism from some society groups, but from another hand, they can effectively attract attention and reach the target group. 

In such case need no words.  

 

The billboard before rain

 

...anf after a rain

 

 

 Just one question: did German teenagers shower this billboard at sunny weather? ;-)