This image shows some of the the amazing stone work at Chetro Ketl in Chaco Canyon. Seen against the backdrop of the canyon walls, it is not hard to imagine a bustling city with people going about their daily lives. It is also easy to see how the Anasazi took some of their building techniques from the world around them. These stone walls, some up to two feet thick, and interwoven, created an impregnable barrier to weather and enemy alike. They also provided a solid base for the two upper stories. In all, Chtro Ketl is thought to have contained 550 rooms in a complex that covered almost three acres.