help react pls

HTML
----------
<!DOCTYPE html>
<html>
    <head>
        <title>News</title>
    </head>
    <body>
        <div id="root"></div>
        <script src="js/react/react.js"></script>
        <script src="js/react/react-dom.js"></script>
        <script src="js/react/browser.min.js"></script>
        <script type="text/babel" src="js/app.js"></script>
    </body>
</html>

APP.JS (NOT WORK)
------------
ReactDOM.render(
    <h1>Hello, world!</h1>,
    document.getElementById('root')
);

APP.JS (WORK)
------------
ReactDOM.render(
    React.createElement('h1', null, 'hello, world'),
    document.getElementById('root')
);

SERVER.JS
-------------
var express = require('express'),
    app     = express();

app.set('port', (process.env.PORT || 3000));

app.use('/', express.static(__dirname));

app.listen(app.get('port'), function() {
    console.log('Server started: http://localhost:' + app.get('port') + '/');
});