In Final Fantasy XIV, what is the name of the Deep Dungeon that was introduced in the expansion pack, Heavensward?

In Final Fantasy XIV, the deep dungeon introduced in the expansion pack Heavensward is called the Palace of the Dead. The Palace of the Dead is a unique and challenging dungeon with its own set of mechanics and progression system. It offers players a different experience from traditional dungeons and raids in the game. Players can explore its depths, face various enemies, and advance through floors to unlock new challenges and rewards.