NOVA: Making North America

Part 2 of 3. How life emerged in North America; and why the continent was home to many iconic dinosaurs, including the T. rex. Included: a diving expedition off the Bahamas spotlights rare living fossils; and a trip to the Badlands of North Dakota and desert wilderness of southern Utah highlights dinosaur discoveries. Also: evidence of the catastrophic asteroid impact that killed off the dinosaurs; and why North America was mostly primate-free until the arrival of humans.