[edit] Henesys Hunting Ground

Henesys Hunting Ground - Suitable for All classes from level 10 to 30, better for ranged classes.
Monsters Blue Snail (Lv 2, 15HP, 4xp, floor 1, 2*)
Red Snail (Lv 4, 45HP, 8xp, floor 1, 3*) Shroom (Lv 2, 20HP, 5xp, floor 1) Slime (Lv 5, 50HP, 10xp, floor 2, weak to lit) Stump* (Lv 5, 65HP, 8xp, floor 3, 4, weak to fire) Orange Mushroom (Lv 8, 80HP, 15xp, floor 3) Green Mushroom (Lv 15, 250HP, 26xp, floor 4)

Notable Drops Pan Lid, Zeco, 100% Cape scroll for DEX.
Pros Monsters spawn very quickly
Efficient for all classes Highly categorized, with different monsters at different floors and levels.

Cons Lots of people in virtually every channel
Massive lag Massive kill stealing

Comments Pick your floor, and kill away. The monsters spawn like no tomorrow. Great place to train, but get ready to get KSed a lot, unless you are a mage or rogue with claw, then be prepared to ks and get defamed. Divided into four floors. Pick the floor you can kill easiest.
Alternatively, players go to the second or third hunting ground if you don't want to be KS'ed, which are hidden streets at the very tops of the hunting grounds. They are accessed by climbing the rope that is seen hanging down from the sky at the top of each hunting ground. However, the spawn rate isn't as high since there are less players. Still, 3rd job show offs sometimes ruin your day.

http://strategywiki.org/wiki/MapleStory/Training_Guide