To ensure Babel converts our JSX, we include within the Body.
We used the ReactDOM.render method to render elements to the DOM. A method being a function attached to an object. This method takes 2 arguments; What (JSX/element) and Where (where we want it placed in the DOM).
ReactDOM.render( <h1>Hello World</h1>, document.getElementById("app") );
Voila! We can now see "Hello World" in our browser!