Wickenshire East on OSGrid has a Labyrinth, it is amazingly well built and a highly immersive space so be prepared to lose time. I lost about an hour but it was definitely worth every minute of it. I highly recommend you go and take a look for yourself.
While I was there I got a notecard that gives a description of the environment and some information about the creator:
Lara Nguya welcomes you to Wickenshire East Labyrinth
For best effects turn your viewer environment to Midnight. Over most of your travel through passageways, you will find it easy to fly, for the passages have been designed to make navigation smooth for you. However, by flying, you may miss many of the sounds that are to be heard everywhere in the Labyrinth. Nearly all sounds are triggered by the nearness of your avatar. You won’t hear many sounds if you use zoom or cam around. The Labyrinth has been designed as an immersive environment for your maximum enjoyment.
There are many grotto’s, oubliettes and caverns to see on your way. An oubliette is a cavern or grotto with a single entrance or exit. It is usually ornately decorated for an immersive experience. The name ‘oubliette’ comes from the French word ‘oublier’, which means to forget.
I have been to this region a few times since starting to write this post, on tonight’s return to get some information I decided to make a video of the Labyrinth and had so much fun filming and editing it. There a few spots in the video where I had some frame dropping when recording and however many times I did a retake the screen ripping is still there.