.htaccess rule to ignore .htm & .html extension?

Hi there,

I need my site to ignore the trailing .htm and .html for the entire domain.

I am trying to do this for the entire domain.
It is a sub domain of the main account and DOES NOT have Wordpress or other script on it. It just a simple site with html docs/images etc.

But there are going to be many of these little site so I do not want to write out a rule for each file. I need one rule for the entire domain. Is that doable?

I have searched the documentaion and can't find it in an understandable form!

Thanks