Sir David Attenborough presents this landmark documentary which brings to life, in unprecedented detail, the lost world of the very last days of the dinosaurs. Searching in the hills of North Dakota, palaeontologist Robert DePalma makes an incredible discovery in a prehistoric graveyard known as Tanis - fossilised creatures, astonishingly well preserved like the bodies found at Pompeii.
Whilst DePalma hunts for the evidence that can shed light on the final days of the dinosaurs, state-of-the-art VFX transports Sir David back in time to the Late Cretaceous to witness the creatures who lived at Tanis at the end of the Age of Dinosaurs. Meanwhile, cutting edge scanning techniques reveal fossilised secrets that could change our understanding of the dinosaurs' extinction once and for all.

Experience with David Attenborough the wonders of a lost world like never before in this epic series. Travel back 66 million years to when majestic dinosaurs and extraordinary creatures roamed the lands, seas, and skies.
In the first episode, a pregnant Tuarangisaurus is in distress and her young calf can sense it as she travels waters that are home to the ocean's deadliest predators.

In the second episode, Dreadnoughtus males compete for the right to mate. Lizards are hunted by Velociraptor among a group of sleeping Tarbosaurus. A Mononykus forages for termites and investigates new food options after a brief rainstorm. Several types of dinosaurs congregate around a watering hole in Mongolia.
Above the deserts of North Africa, aerial combat ensues as male Barbaridactylus pterosaurs fight for the attention of females below. A herd of Secernosaurus brave the harsh gypsum dunes in search of nourishment.

In the third episode, a Velociraptor hunts pterosaurs on a cliffside by a waterfall. A battle-scarred Tyrannosaurus nurses his wounds and encounters a newcomer. With its feathered body and duck bill, the eight-ton Deinocheirus wades through an Asian wetland in search of relief from pesky biting flies.
A female Quetzalcoatlus builds and guards her nest. A mother Masiakasaurus and her family hunt crabs. Elasmosaurs enter an estuary in search of fish.

In the fourth episode, Dromaeosaurs stalk a hadrosaur herd as they cross a freezing river. Male Ornithomimus raid rival nests to bolster their own. Olorotitan raise their offspring on fertile volcanic fields but contend with biting mosquitoes.
Troodontids hunt mammals flushed out by a forest fire. A juvenile Antarctopelta scours the forest for a new winter den. Within the snow-covered forest, a tense standoff develops between ancient rivals, Pachyrhinosaurus and Nanuqsaurus.

This episode explores the palaeogeography of Earth over millions of years, and its impact on the development of life on the planet. Tyson starts by explaining that the lignin-rich trees evolved in the Carboniferous era about 300 million ago, then explains on the nature of plate tectonics that would shape the landmasses of the world and the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals as the dominate species on earth. Earth's landmasses are expected to change in the future and postulates what may be the next great extinction event.