In 1991, a group of coders named Phenomena released a demo meant for a standard Amiga 500, titled Enigma.
That demo started with a number of subverted demoscene stereotypes, followed by a real-time flight through a flat-shaded, untextured polygonal environment. Back then, virtual reality technology was in its infancy and going through an unceasing mediatic exposure: showing a (very simple) virtual world in a demo was a sure way to popularize it.
Another part of the demo showed a looping, pre-rendered 4-frame raytraced animation, again exploiting the hype for renderers, modellers, CGI and VR, which laypeople could not really distinguish yet.
More recently, I heard a high quality audio remix of the demo soundtrack, and that was the incentive I needed: I decided to make a high definition, high detail remake, to have high quality visuals to go with the audio. Part of the demo took place on Mars, and coincidentally, I had already made an explorable rendition of Cydonia (arguably, the most aesthetically interesting region of Mars), purely for the curiosity to see it in first person, so I decided to use it in the remake.
Furthermore, I decided to make some VRML worlds out of several parts of my remake, to let anyone explore the corresponding parts of the demo. Moving around those environments was something I always wanted to do, and now it's actually possible, so it would have been a waste not to go ahead and do it.
UPDATE: The latest version of Firefox, if run from Windows XP, is incompatible with Cortona 3D Viewer. The solution is Firefox Portable.
If you cannot open VRML files anymore, you ought to download Firefox Portable 43.0.1 and just unzip it wherever you want. Portable versions do not need to be installed and will not interfere with the existing installation, so you can use this version to explore VRML files only. If you have Windows XP and don't have Cortona 3D Viewer installed yet, you should install version 6.0.
Starfield in a box
Cydonia region on Mars (based on an ESA photograph)
Mars, Phobos and Deimos (astronomically correct distances)