This is one of our old server worlds. It was named Second World and we started it the day BETA 1.8 came out.
It has 3 cities one of which has a big glass dome over it. As can be seen on the screenshot it suffers from biomechanges (has actually changed several times) due to updating the game to newer versions.
This is one of our old server worlds. It was named Pirateworld.
This world was generated when the jungle biomes showed up in 1.2.1 and we used to have a base in the treetops of a jungel that used to be at x: 0 Z:0.
It seems however that something weird has happened because when I was starting up the world to take a screenshot the jungel was no longer there, instead there was another weird landscape so unfortunately the base is probably lost.
There is however another base in the world that you can check out if you want to. There should be lots and lots of recourses in it so it might be a good place to loot and then start your own base.