If you explore all of the major geographical areas in the game, you will earn the title "The Explorer." You can find out what areas you haven't explored yet by clicking the Exploration button in the achievements window and then selecting the area you're exploring (for example, Outland). If you click any of the regions listed there, you will see which sub-zones you're missing. You can even track the achievements so you can see which zones you still need to visit.
Most of the achievements in the "Exploration" category are fairly self-explanatory, most are granted simply for fully exploring a single zone or all of the zones on a continent, with the "World Explorer" achievement as a reward for those who find a way to fully explore every zone in the game.
General Exploration Achievements
There are five general achievements in the "Exploration" category. "Explore Eastern Kingdoms" and "Explore Kalimdor" are awarded to players who fully explore each zone on either continent. Both are worth 25 achievement points. Those who fully explore Outland will recieve 25 points and the "Explore Outland" achievement, while those who reveal all the sections of every zone in Northrend get 25 points and the "Explore Northrend" achievement, along with the [Tabard of the Explorer]. The "World Explorer" achievement is for those who manage to accomplish all of the previous four exploration achievements. It's worth 50 points and grants the title "The Explorer."
Eastern Kingdom Exploration Achievements
There are 25 zone exploration achievements in the Eastern Kingdoms. Each is granted for fully revealing the map in it's respective zone and is worth 10 points. They are: "Explore Elwynn Forest," "Explore Dun Morogh," "Explore Tirisfal Glades," "Explore Eversong Woods," "Explore Loch Modan," "Explore Westfall," "Explore Wetlands," "Explore Silverpine Forest," "Explore Ghostlands," "Explore Redridge Mountains," "Explore Duskwood," "Explore Hillsbrad Foothills," "Explore Swamp of Sorrows," "Explore Badlands," "Explore Stranglethorn Vale," "Explore Alterac Mountains," "Explore Arathi Highlands," "Explore The Hinterlands," "Explore Searing Gorge," "Explore Blasted Lands," "Explore Burning Steppes," "Explore Deadwind Pass," "Explore Western Plaguelands," "Explore Eastern Plaguelands," "and "Explore Isle of Quel'Danas."
Kalimdor Exploration Achievements
The Kalimdor exploration achievements are similar to those in the Eastern Kingdoms. Each of the 20 is earned by fully exploring a zone and each is worth 10 points. The Kalimdor Achievement titles are: "Explore Durotar," "Explore Mulgore," "Explore Teldrassil," "Explore Azuremyst Isle," "Explore The Barrens," "Explore Darkshore," "Explore Bloodmyst Isle," "Explore Ashenvale," "Explore Thousand Needles," "Expore Stonetalon Mountains," "Explore Desolace," "Explore Dustwallow Marsh," "Explore Feralas," "Explore Tanaris," "Explore Azshara," "Explore Felwood," "Explore Un'Goro Crater," "Explore Moonglade," "Explore Silithus," and "Explore Winterspring."
Outland Exploration Achievements
There are achievements associated with exploring each zone in Outland, as well as two achievements related to finding and killing certain rare spawn mobs.
Like the old world, the individual zone exploration achievements in Outland are worth 10 points a piece. They are: "Explore Hellfire Peninsula," "Explore Zangarmarsh," "Explore Terrokkar Forest," "Explore Nagrand," "Explore Blade's Edge Mountains," "Explore Netherstorm," and "Explore Shadowmoon Valley."
The other two exploration achievements are related to the following list of "extremely rare and hard to find Outland creatures." "Medium Rare" is the reward for finding and killing one creature on the list and is worth 10 points. "Bloody Rare" is for those who find and kill all 20 mobs, it's worth 25 points. The mobs are: Ambassador Jerrikar, Bog Lurker, Chief Engineer Lorthander, Coilfang Emissary, Collidus the Warp-Watcher, Crippler, Doomsayer Jurim, Ever-Core the Punisher, Fulgure, Goretooth, Hemathion, Kraator, Marticar, Mekthorg the Wild, Morcrush, Nuramoc, Okrek, Speaker Mar'grom, Voidhunter Yar, and Vorakem Doomspeaker.
Northrend Exploration Achievements
There are 9 "Exploration" achievements for Northrend Zones: "Explore Borean Tundra," "Explore Howling Fjord," "Explore Dragonblight," "Explore Grizzly Hills," "Explore Zul'Drak," "Explore Sholazar Basin," " Explore Crystalsong Forest," "Explore Storm Peaks," and "Explore Icecrown," each is worth 10 points.
Like Outland, there are two Northrend achievements related to killing specific rare spawn mobs on the continent. Kill one of the following and recieve the "Northern Exposure" achievement, worth 10 points. Kill them all to recieve the "Frostbitten" achievement and 25 points. The mobs: Aotona, Crazed Indu'le Survivor, Dirkee, Fumblub Gearwind, Griegen, Grock, High Thane Jorfus, Hildana Deathstealer, Icehorn, King Krush, King Ping, Loque'nahak, Old Crystalbark, Perobas the Bloodthirster, Putridus the Ancient, Scarlet Highlord Daion, Seething Hate, Syrean the Bonecarver, Terror Spinner, Tukemuth, Vigdis the War Maiden, Vyragosa, and Zul'Drak Sentinel. There are a multitude of achievements for those who are driven to explore every nook and cranny of the lands of Azeroth, Northrend, and Outland.