30 Years of National Geographic Specials

David Attenborough and scientist Johan Rockström examine Earth's biodiversity collapse and how this crisis can still be averted.

"Kon-Tiki" was the name of a wooden raft used by six Scandinavian scientists, led by Thor Heyerdahl, to make a 101-day journey from South America to the Polynesian Islands. The purpose of the expedition was to prove Heyerdal's theory that the Polynesian Islands were populated from the east- specifically Peru- rather than from the west (Asia) as had been the theory for hundreds of years. Heyerdahl made a study of the winds and tides in the Pacific, and by simulating conditions as closely as possible to those he theorized the Peruvians encountered, set out on the voyage.

Ashes and Snow, a film by Gregory Colbert, uses both still and movie cameras to explore extraordinary interactions between humans and animals. The 60-minute feature is a poetic narrative rather than a documentary. It aims to lift the natural and artificial barriers between humans and other species, dissolving the distance that exists between them.

Veteran naturalist Sir David Attenborough tells the story of a remarkable group of gorillas, from his first encounter in the '70s to the present day.