While data is certainly important in any application, you can't have an application without a user interface at all. On the web, this means that you have a combination of DOM elements (to display information to the user) and event handlers (to receive input from the user). In Backbone, both of these things are managed by Views; in fact, it's only fair to say that Views pretty much control all the input and output on a Backbone-powered site.

Just as Models wrap an attributes object and Collections wrap a models array, Views wrap a DOM element inside a property called el. Unlike attributes and models, however, el is not hidden, and Backbone doesn't watch it for changes, so there's nothing wrong with referencing a View's el directly:

someModel.attributes.foo = 'bar'; // don't do this
$('#foo').append(someView.el); // feel free to do this

To create a new View subclass, simply extend Backbone.View in the same way as you created new Model and Collection...