Sand

I am one.
I am one million.
I travel all over the world.
I sit in one place for many years.
I get in your shoes.
I get in between your toes.
I have children playing with me.
I have adults making great thing from me.
I am everywhere and in everything.
I am as old as the earth and the stars.
I bring joy to everyone.
I am the sand on the beaches.
I cover every part of the world.
I am used to help build houses for all.
I know no boundaries or borders.
I treat everyone the same.