Everquest has 270 zones, 11 Explorable Continents and hundreds of different raid encounters. Below are pictures of each continent and a picture of the world map. If you're looking for a huge expansive world in a game that you can never completely explore, EQ is your game.
South East Antonica
Odus
Faydwer
Kunark
Velious
Luclin
Luclin Underground
Planes
Planes of Power
Omens of War
Depths of Darkhollow
Katta Castrum
The Void