In the Hallowfall zone of World of Warcraft: The War Within, there's a hidden chest called the Smuggler's Treasure, filled with goodies and reputation points.
To find the chest, you'll need to track down a key hidden on a dead Arathi near the Aegis Wall.
Once you have the key, head to the coordinates 55.16 and 51.86, where the chest is perched on a mountain edge.
Be careful, though, as enemies might lurk nearby, so be prepared to fight your way to the treasure!