DIE GRÍSSTE WASCHSTRASSE DER WEL (sorry the video is only in Germany!)...
größte Waschstrasse der Welt - Galileo - Video&PL=Facebook&width=396&KN=Galileo&height=224
I hope the above link works. ? Here is a story on the largest car wash in the World: Stuttgart Germany. Its located on the B14 at the top of the hill as you go into Bad Cannstadt.
They hold the world record of washing over 4K cars in one day! On a normal day they wash 2,800 cars. Over 100 workers at the car wash. And they also do high end car detail service as well: ~2,500 euros.
A normal car wash program starts at 6 euros and goes up to 14 euros. Cleaning the inside costs extra ~18 euros.
Quite an interesting place!