Walter Alvarez, professor of geology in the Earth and Planetary science department, presents "Earth History in the Broadest Possible Context." Alvarez recounts revolutions in geology, his work in Egypt, Libya and Tunisia as well as his interests in the Sahara, the Nile and the Mediterranean. Alvarez also tells the tale of the Berkeley Theory, in which dinosaurs were killed by an asteroid impact, developed in collaboration with his father, Nobel Prize winning physicist Luis Alvarez. Alvarez also unveils ChronoZoom, a new tool for the emerging field of "Big History" that makes browsing the past at all scales comprehensible like never before.