Chimney Rock in southern Colorado stands at the northernmost extent of Chacoan culture. There were numerous Chacoan villages along the nearby river and one atop the knife-edged ridge that leads to the paired pinnacles. On the ridge near them is a kiva whose southern wall aligns with a gun-sight view between the rocks where the San Juan Mountains can be seen in the distance. It also aligns with the furthest north rising of the full moon in its 17-year course. Tracking this course seems to be the purpose of the various alignments of the kiva and the rocks.
From Chimney Rock light at a distant Chacoan ruin far to the south can be seen and this light can also be seen at Pueblo Alto along the Chaco Canyon rim. It would have been a simple matter to transmit messages back and forth.