This one was pretty quick. An extruded box, with subdivisions all the way up. One side had polys removed every two to three subdivisions, to allow light (as I had the idea of setting up a camera inside the box). A bend modifier applied, and then Greeble was employed to mix things up a bit. Slice modifier was used to open up the box from inside and to get a wider perspective when rendering. The slithery vines were due to the Ivy plugin, which was at first just an experiment which turned out good.
Post render, haze/diffuse glow was added as well as a slight chromatic and blur to the image. The darker (almost night) version was very similar in approach, although I couldn’t resist lighting things up a bit. Curiously, the render time was somewhat shorter as I used a HDR map instead of sun/sky. Not bad for a 30 minute experiment. Another satisfying doodle.