Wurm Online is a sandbox RPG in a virtual world in which players can choose to roleplay almost any scneario they wish. There are several servers, each with different purposes and/or modes. some feature timed sessions, others are for PvP, and some are completely PvE.
There are no classes or levels in Wurm Online; instead the game focuses on skills that the person chooses to advance. As skills are trained, they become harder to train, since a master has little room for improvement. One will also find very few NPCs - the world is very player driven.
The world in Wurm is dynamic - resources must be discovered and are renewable. If you cut a tree, it will eventually grow back. Crafting with these resources is also an extremely deep system as it takes at least several detailed steps to create new items. Essentially,Wurm is a real life simulation of a rural resident in a simple time and place. The game requires a subscription, but at least two months' time must be purchased for 10 euros (around $15) at a time.