On Friday, September 21st, President Obama added Chimney Rock to the list of National Monuments by utilizing the Antiquities Act. Chimney Rock National Monument is comprised of 4,726 acres and is located in southwestern Colorado in the San Juan National Forest. This area is extremely important to modern Pueblo Indians because their ancestors inhabited this land 1,000 years ago. Some deduce that the Ancestral Pueblos peoples built their "great house" in order to get a front row seat for the major lunar standstill. From the great room (built in 1076) the twin pillars of Chimney Rock frame a narrow piece of sky; every 18.6 years the full moon rises perfectly between the spires and is only visible from this vantage point. Watch this video about the lunar standstill at Chimney Rock.