They are computer animations which create virtual "music videos" in virtual environments. The playlist is called "Animusic" computer animated music, uploaded by YouTube user Effchen.
The 3D-rendered computer graphics are stunning, and really mind-bending if you take the time to watch them.
The great thing about computer animation is that we can create & experience completely virtual spaces that look realistic- but are in fantastic environments with seemingly impossible instruments & objects.
The first video I saw was "Gyro Drums," a crazy take on the percussion solo.
"Resonance Chamber" features classical string sounds, The video features a strange, but elegant-looking, hybrid instrument. It is being played by spider-like mechanical fingers.
There are also more futuristic & hi-tech themes, like "Fiber Bundles". Here, a rhythmic synergy is created between the light and the music to create a synesthesia-like effect.
I would recommend checking out the whole playlist, for more of these awesome videos.
Once virtual reality (VR) applications really take off, there will be no limit to the virtual spaces & novel experiences that the human mind can explore.
The official website for Animusic sells the videos on DVD & Blu-ray.