You can find Ahn’kahet: The Old Kingdom dungeon within Dragonblight.
The coordinates are (26.7,50.4)
Make your way to Azjol Nerub on map then go down into the hole in the ground, this will take you to The Pit of Narjun.
You can follow the path through the tunnel or jump down one of the holes, this will take you near to the dungeon entrance. Next to the summon stone there is a path, go down the path into the room where the dungeon is.
In the Befouled Terrace you need to deactivate x2 Ancient Nerubian Devices. They are located on two platforms, deactivate them to fight 2nd boss Prince Taldaram.
1. Elder Nadox
/i Deals ticking nature damage to a player. Kill Swarmers quickly to avoid boss enraging them with Brood Rage. Kill Guardians away from other mobs.
2. Prince Taldaram
/i Flame Sphere floats towards a player & does fire damage. Boss vanishes then appears behind a player. Embrace of the Vampyr deals ticking shadow damage & stuns.
3. Amanitar (Heroic Boss)
/i Roots a player & deals ticking nature damage. When shrinks all players kill Potent Fungus. Poisonous Mushroom release Poison Clouds when killed.
4. Jedoga Shadowseeker
/i Spins hitting all nearby players & knocks back. Avoid lightning cloud on floor. Uses Lightning Bolt. Kill Volunteers before they reach boss.
5. Herald Volazj
/i Inflicts lots of high shadow damage. During Insanity you need to kill all the Twisted Visages of your allies.