Using UI-Router without defining urls


I have a codepen example where I'm routing view inside a side menu (drag right to open it up) and changing view to create a pseudo sub-menu navigation.

Here's an example state provider from the codepen

.state('tabs.facts', {
  url: "/facts",
  views: {
    'home-tab': {
      templateUrl: "facts.html"

What I'm wondering is if the urls can be removed and still work. I've tried and haven't had any luck and waned to know if anyone who knew UI-Router knew if there was to set up state that didn't need any urls. Any ideas or help is appreciated.