I've never done a very good job of exploring Pteron. I would get caught up in the main build and not realize the other hidden worlds that are available. Don't make this mistake.
Each of the options is thematically similar (fantasy/futuristic) but at the same time offers something completely different to explore.
One of the more intriguing aspects of this exploration is that changing your camera angle will completely alter your understanding of your experience. There isn't room in this post to give examples and I wouldn't want to spoil your sense of discovery anyway. Do try it for yourself and see what happens. :)
Something that all 5 locations have in common is the quality of not only vision but execution. This has always been one of the superior builds in Second Life and that hasn't changed. If you want peace and beauty and wonder, go spend some time on Pteron.