How can you wash (Wuzu) if there is no water?

Question

How can you do wuzu if there is no water? Is it still a mandatory (farz) to pray if you cant find water or clean water to do wuzu around you?

Answer 1

I forgot the name of it but i know you can do wuzu with only sand (dirt) if necessary.

Answer 2

Wow! That's a really neat awnser!