Nothing too special, but thought I'd share since it took me a bit of work still :) For those that like this kind of project at least!

The portal gate we used with a mod is still inside, but you can tear it down easily, it's only stone blocks.

I couldn't really figure out how to do the inside, but up to you to furnish it~ Since entering from the top is rather hard in Minecraft without flying mods, the entry is from the bottom, like in some of the games (Other M and Prime 3 I think?)