Answer:
From the Big Bang to the present day (or from the beginning to the present, if you wish).
Step-by-step explanation:
Big History, as an academic field of study, is supported by a variety range of disciplines. This multidisciplinary approach tries to explain the human heritage under the study of culture, and society. Which means that disciplines such as Anthropology and Social Studies are valuable allies in the Big Story approach. Another important aspect of this field is the conception of cause-and-effect (or action-reaction). According to this idea, all human actions during History created a reaction that, one way or another, led him to go ahead. History, by this approach, is linear, following a straight line.