As early as the twelfth century A.D., the settlements of Chaco Canyon in New Mexico in the American Southwest were notable for their "great houses," massive stone buildings that contain hundreds of rooms and often stand three or four stories high. Archaeo

The main topic of both the passage and the lecture is theories of how the Chaco great houses are used. According to the passage there are three competing theories. However, the professor finds the idea questionable, citing three reasons to repudiate all the theories mentioned in the passage.

First, the passage mentions a theory that proposes that the huge buildings were residential, housing hundreds of people. The passage introduce the buildings as old versions of recent apartment buildings. However the lecturer repudiates the theory by pointing out that although from the outside they resemble apartments, there are strong evidences inside that cast doubt on being residential. He explains that there are not enough fire places for accommodating that population in it. there are enough fire place for about ten families but enough space for more than one hundred families.

Second, the passage suggests that the buildings probably were used for storing food supplies especially grain maize. On the other hand, the professor maintains that although this theory sounds plausible, there is not enough evidence. If the buildings were used as an store, maize and big containers of it should be found in the excavations. So, that cannot be acceptable because there is no evidence of containers or maize.

Third, the passage asserts that the houses were used as ceremonial centers. The author proves this suggestion by making the point that excavations revealed a large number or old material like broken pots. On the Contrary the lecturer refutes the last theory by explaining that the excavations revealed many other material that reject this theory. Building material like sand, rock and also construction tools suggest that the place was used for piling construction trash. The professors further describes that the broken pots may be left from the meals of the workers and have nothing to do with social gatherings.