index.html

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>React! React! React!</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
</head>

<body>
    <div id="container"></div>
    <script type="text/babel">
        ReactDOM.render(
            <h1>Sherlock Holmes</h1>,
            document.querySelector("#container")
        );
    </script>
</body>

</html>