In the traditional construction of a hogan, the Diné dwelling house, a hole is cut in the roof in order to let smoke from the hearth fire below out of the room. The hole is usually placed off-center and aligned above the rock slab that serves as a hearth so that as the smoke rises it leaves the residence. In later, more modern hogans, flues that facilitated the removal of smoke directly from the rock-slab or adobe hearth have replaced the hole in the roof.