why does klaus want to break the curse anyway, he has witches can't he just get a ring and then go out in the sun?

I think that Klaus wants to break the curse because werewolves seem to be the only thing that can harm "the orignals". So, if the curse is broken by Klaus, he`s technically invincable.

I think it's a conquest thing. Without the curse, the vampires could band together and rather than having to hide they could enslave humanity. It could also be the glory of breaking the curse.

Just a thought P:.

Also I'm sure he has a ring already, I mean, come on, he's fucking Klaus xD.

Klaus doesn't need a ring. He is evil and wants to Just kill Katherine and Elena's line to surive.
They need to die to make him stronger.