There's obviously much more hidden meaning here than I could find in a lifetime.

…but the yin and yang theme mixed with stylizations of sun & moon on ancient Twilight Sparkle herself stand out wonderfully, even down to the forms of her wings. I'm also delighted to see the dendriform elements of the tendrils reaching down into her comfortable little tower, plus the tree motif for the fresco regarding her friends' cutie marks. This old place is quite lavish in art, with so many memories of her times as a young princess, plus a nice shout-out to older Spike and the other princesses, plus some items that are probably for other events in the show (or in the future?). Too bad the frescoes on the right (particularly the upper) are obstructed because seeing Twilight's tail like that makes me think of her sitting, and I have to wonder what she's examining or listening to in the stillness of that barren landscape.

The artifacts, tomes, ink, scrolls, tools, etc. surrounding her prove that she kept her charming quality of getting absorbed in things. The writing on the scrap of paper near the center is a tad bittersweet, speaking of her friend and teacher and the others perhaps having move on to another plane, but it's hopeful that she will remain to keep harmony alive. Also, cute how that paper is also folded in a way that sort-of mimics her cutie mark.

You did a spectacular job on all of the forms and especially the textures; the decorative form of shading on Twilight herself and on the vines is fantastic. It's cool how the one that rises past her younger form and her impressive star is ethereal and lets other things show through that we normally wouldn't see (like young Twilight's left eye open vs. real Twilight's right eye). Wonderful job on the map and all of the various writings too, and more so that it's a bit messy as she goes from item to item as her thoughts sometimes flutter like a butterfly in flight. Also, the missing stone makes me think (or makes me hopeful) that there's a hidden chamber or passageway touching on this sanctuary, even if not directly connected.