Best free "massively multiplayer" games

Massively multiplayer games take the idea of online gaming and crank it up to an entirely different scale. Instead of playing in a world populated by a handful of players, you share a persistent universe with thousands of other people, each pursuing their own goals, ambitions, and questionable life choices. You might become a heroic adventurer, lead a powerful guild, trade goods, explore dangerous territory, or simply wander around wondering what everyone else is doing. Other players can become trusted allies, fierce rivals, or complete strangers who mysteriously steal the monster you were about to defeat. The real appeal is the living world itself: it continues to evolve, players come and go, communities form and disappear, and something is always happening somewhere—even while you’re offline.