It is the most memorable moment of Sir David Attenborough's broadcasting career. A short sequence of his encounter with a group of playful mountain gorillas in a forest clearing in Rwanda.
"There is more meaning and mutual understanding in exchanging a glance with a gorilla than any other animal I know," he tells the camera, as a female gorilla observes him from just a few feet away.
The footage for his 1979 Life on Earth series was not just unexpected, it said something profound about our close relationship with the natural world.
As Sir David approaches his 100th birthday on 8 May, he has taken part in two documentaries that look back at that unforgettable meeting and the dramatic story of what became of that gorilla family.
Making Life on Earth: Attenborough's Greatest Adventure returns to 9 January 1978, the day Attenborough and the team arrived in the Virunga Mountains.
