The Amani Catacombs are a series of mummy-infested forest troll crypts in the Ghostlands, located northeast of Tranquillien Village in the mountains. To get there, you should first obtain the quests H  ω τ ϖ and H  ω τ ϖ. Then, head out of Tranquillien and take the first fork right in the road. If you look on your map, there should be a light blue area in the mountains close to your current location. Head up this path, through some Shadowpine Oracles and into the crypt. You should at least be level 16 - 18 when entering this area, as there are many mobs roaming inside the catacombs of this level.
The Amani Catacombs are also home to many rogue quests, including H  . These quests introduce new rogues to the lock-picking skill, requiring the rogue to pick locks on the scattered beginner difficulty chests in the area.