Thakan'dar is a fog shrouded valley outside Shayol Ghul, where Myrddraal swords are forged. Despite being in the far north, surrounded by ice, Thakan'dar itself is dry. Most times, there are human prisoners there, waiting to be sacrificed by the forgers to temper the blades.
In the Last Battle, the forces led by Rodel Ituralde seize Thakan'dar. The forges are destroyed, and the human prisoners are freed.
"The great sea of fog, rolling and crashing in silence against the black cliffs, the fires of the forges glowing red beneath, and lightning stabbing up into a sky fit to drive men mad." (Fain, The Shadow Rising, Chapter 22).