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.

The disappearance and fate of the tomb of Alexander the Great in Alexandria is among the most momentous and tantalising of all the mysteries we have inherited from the ancient world. Generations of scholars and historians have succumbed to the allure of the quest.
Now archaeologist Pepi Papakosta is on a mission to find Alexander the Great's lost tomb. Excavating in a public garden in the center of Alexandria, Egypt, the city he founded 2,300 years ago, she has discovered a rare marble statue of Alexander, Greek treasures and secret tunnels. But Pepi's biggest find is an extraordinary discovery even she was not expecting.

Will explore the strategy, deception and feats of engineering plants use to thrive in the changing weather of different seasons. In the face of conditions ranging from ice and snow to raging fires, survival is often a question of perfect timing - particularly when contending with intense competition and surprising predators.
In this episode, David Attenborough travels to Finland to show one of the most extreme examples of seasonal plant life in the Arctic Circle. He also travels to California to see how climate change is affecting giant sequoias. These ancient trees like all other seasonal plants depend on the predictability of the seasons and our current changing climate threatens their survival.

Thanks to stunning reconstitutions with computer-generated images, this documentary retraces the manufacturing secrets of the largest and most exceptional city of Antiquity: Rome, the capital of the Mediterranean world. Three of its most emblematic monuments come to life. The Pantheon and its majestic dome, the sumptuous palace of Nero which covered a quarter of the city, and finally the legendary Colosseum, the largest Roman amphitheater ever built.

Located in Central America, Tikal is one of the largest of the ancient cities of the Mayan civilization. Occupied for more than a millennium, Tikal, founded in the 8th century BC and nestled in the jungle of Guatemala, will have up to 12,000 structures and reach over 2 million inhabitants.
This episode shows its extraordinary pyramid-temples, designed with human power alone. Thanks to new technologies, the ancient Mayan city is revealed there, entirely reconstituted in 3D synthetic images.

Feast your eyes on a reconstruction of the mega-city and its amazing buildings. Alexandria, built in the middle of rancid marshland, had become in less than a century, the greatest city of the Mediterranean. An ideal position at the crossroads of east and west, and one that brought her great riches. Huge, modern, gleaming white and cosmopolitan, like no other in antiquity, it created its own identity.
While the beauty of its planning, its great arteries, its temples and its ports would be equalled only by its openness to the rest of the world. And the monumental achievements of its sovereigns, still shrouded in mystery, we'll never cease to fire our imagination for millennia to come.