Aztec Ruins National Monument - http://www.nps.gov/azru/

This is the new sign that was recently installed at the park, in December 2011

Around 1100 A.D. ancient peoples embarked on an ambitious building project along the Animas River in northwestern New Mexico. Work gangs excavated, filled, and leveled more than two and a half acres of land. Masons laid out sandstone blocks in intricate patterns to form massive stone walls. Wood-workers cut and carried heavy log beams from mountain forests tens of miles away. In less than three decades they built a monumental “great house” three-stories high, longer than a football field, with perhaps 500-rooms including a ceremonial “great kiva” over 41-feet in diameter.
A short trail winds through this massive site offering a surprisingly intimate experience. Along the way visitors discover roofs built 880 years ago, original plaster walls, a reed mat left by the inhabitants, intriguing “T” shaped doorways, provocative north-facing corner doors, and more. The trail culminates with the reconstructed great kiva, a building that inherently inspires contemplation, wonder, and an ancient sense of sacredness.