What is vaults of atziri?

Vaults of Atziri is a map area in the video game Path of Exile. It was added to the game in the Ambush and Invasion leagues in March 2014. The map area contains several rooms filled with treasure chests and unique enemies, including Atziri's minions. The boss of the map area is Atziri herself, a powerful and challenging boss that drops valuable loot upon defeat. Players can only access the Vaults of Atziri by purchasing the map from the in-game marketplace or through trading with other players. It is considered one of the more profitable maps in the game due to the high value of its drops.