Given a block container

<div>
 this is a very long string which contains a bunch of characters that I want to break at container edges.
</div>

are there any css properties I can set to force it to break when it reaches the container width, regardless of the contents of the string, for example a break like:

this is a ve
ry long stri
ng which ...

is pretty much what I want. Right now, it seems to always prefer to break at whitespace characters or other special characters (such as /).