Consider taking the Color Cycle Survey

A simple example

Displaying an equirectangular panorama.

<iframe>

<iframe width="600" height="400" allowfullscreen style="border-style:none;" src="https://cdn.pannellum.org/2.4/pannellum.htm?panorama=https://pannellum.org/images/alma.jpg"></iframe>

Standalone

https://cdn.pannellum.org/2.4/pannellum.htm#panorama=https://pannellum.org/images/alma.jpg

API

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>A simple example</title>
    <link rel="stylesheet" href="https://cdn.pannellum.org/2.4/pannellum.css"/>
    <script type="text/javascript" src="https://cdn.pannellum.org/2.4/pannellum.js"></script>
    <style>
    #panorama {
        width: 600px;
        height: 400px;
    }
    </style>
</head>
<body>

<div id="panorama"></div>
<script>
pannellum.viewer('panorama', {
    "type": "equirectangular",
    "panorama": "https://pannellum.org/images/alma.jpg"
});
</script>

</body>
</html>

Pannellum is developed on GitHub by Matthew Petroff.
CDN via KeyCDN.