Question: McElmo Phase refers to a period in the late 11th and early 12th centuries, when drastic changes in ceramics and masonry techniques in Chaco Canyon appeared, archeologists initially suggested that the McElmo influence was brought to Chaco Canyon by immigrants from which site located in Montezuma County, Colorado, it protects some of the best preserved Ancestral Puebloan archaeological sites in the United States?
{'answer': 'Mesa Verde National Park', 'supporting_facts': [['McElmo Phase', 2], ['Mesa Verde National Park', 0]]}