Answer:
There is an ancient invention still used in some parts of the world today that allows people to see through walls. What is it?
What is broken if you say its name?
What falls down but is never injured?
Everybody's got one.
It is a common and favored clothing material among biker gangs and superheroes.
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.