Icarias, also referred to as the Crystal City, was an abandoned city built by Icarium in ancient times. It was located in the middle of the Glass Desert at the time of the Malazans, on the western edge of the continent of Kolanse. The city was made entirely of crystal.
While escaping from the 'Quitors' who destroyed their homeland, the Snake managed to find their way to the city of Icarias. Even as they arrived there, they were attacked by a number of Forkrul Assail, who had been tracking them. Badalle defeated them with one of her poems.
When Mappo Runt wandered through the Glass Desert in his attempt to find Icarium, he stumbled upon the crystal city. While there, he recalled how the crystals composing city had been magically crafted by Icarium so that they would store and return his memories to him.