The Empire of Light
Also known as “The Northern Plane” or simply “The North” it is thought to be very cold and still, though there are tales also of a place within it that is so pleasing and harmonious that anyone reaching it will never want to leave, nor will they eat, drink, sleep or age at all. Little more is known of it.
Popularly, if someone is caught to be in a daytime reverie, or has trouble rousing themselves from slumber, they are said to have “gone to the North”.
See The Planes for information about the other planes.