This is the back side, where the four-story rooms were. The rows of square holes were apprently for supporting rafters to provide floors for the higher rooms. The larger openings with sharp square corners are doors or windows.

Of course, these buildings have been seriously damaged by time, but a harsh environment has been working on them for about a thousand years. It is remarkable that this much has survived.

The chacoans were skilled and careful builders. If they had been around to take care of the buildings, they would probably be perfectly sound.