var app = angular.module('plunker', ['ngRoute']);

app.config(function($routeProvider) {
    $routeProvider
    .when('/', {
        controller: 'homeController',
        template: '<h2>Home</h2>'
    })
    .when('/about', {
        controller: 'aboutController',
        template: '<h2>About</h2>'
    })
    .otherwise({
        controller: '404Controller',
        templateUrl: '404.html'
    });
});

app.controller('appController', function($scope, $location) {
    $scope.isActive = function(path) {
        return $location.path() === path;
    };
});

app.controller('homeController', function($scope) {});

app.controller('aboutController', function($scope) {});

app.controller('404Controller', function($scope, $location) {
    $scope.path = $location.path();
    $scope.back = function() {
        history.back();
    };
});
<!DOCTYPE html>
<html ng-app="plunker">

<head>
    <meta charset="utf-8" />
    <title>AngularJS Plunker</title>
    <link data-require="bootstrap-css@*" data-semver="3.2.0" rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" />
    <script>
        document.write('<base href="' + document.location + '" />');
    </script>
    <link rel="stylesheet" href="style.css" />
    <script data-require="angular.js@1.2.x" src="https://code.angularjs.org/1.2.20/angular.js" data-semver="1.2.20"></script>
    <script data-require="angular-route@*" data-semver="1.2.17" src="http://code.angularjs.org/1.2.17/angular-route.js"></script>
    <script src="app.js"></script>
</head>

<body ng-controller="appController">

    <div class="container">
        
        <ul class="nav nav-pills">
            <li ng-class="{active: isActive('/')}"><a href="#">Home</a></li>
            <li ng-class="{active: isActive('/about')}"><a href="#/about">About</a></li>
            <li ng-class="{active: isActive('/badlink')}"><a href="#/badlink" class="text-danger">Bad link</a></li>
        </ul>
    
        <div ng-view=""></div>    
    </div>

    
</body>

</html>
/* Put your css in here */

.container {
    padding-top: 20px;
}
<h2>404 Not Found</h2>

<p>Oops! Path <code>{{path}}</code> is not found.</p>

<p>You can go <a href="" ng-click="back()">back</a> or <a href="#">home</a> instead.</p>