Aspermere

This is how I see Aspermere. One of the ages Atrus wrote before the events of the first MYST, but that is never seen. I got the idea that Atrus was able to use the waterfalls to intercept the light waves from a crystal, and if arranged correctly can create an image along with other crystals. On top of the mount sits Atrus' first success of a hologram, which is a tree. That tree would be part of a puzzle I thought of, which would consists of the tree looking like an obstacle but that can simply be walked through.
 
Aspermere is surrounded by myst, created by the boiling ocean surrounding it. The main vegetation is a savannah like grass that can be used to make robes and other tools. There is a small village there, but the people escaped Sirrus and Achenar's wrath by using blimps to escape to a nearby hideout.