The idea of a “3D Web” is as old as the Web itself, and in many ways, even older. Today, there are a number of ways to see 3D media on the web. Here is a run down.
WebGL is a standard built into modern browsers, so it does not require any special downloads or plugins. Here’s a introduction to the idea.
Here are some links to examples of content created with WebGL…
Google’s Chrome Experiments
22 Experimental WebGL Demo Examples (Awwwards)
30 amazing examples of WebGL in action (CB Creative Blog)
WebVR and A-Frame
There are some interesting native formats and tools emerging “right now” that enable the ability to see 3D formats on the web as well as in a Virtual Reality headset (if you happen to have one).