LONDON, April 28 -- Celebrations to mark the 100th birthday of renowned British naturalist David Attenborough start next week with a show delving deeper into his milestone 1979 TV series Life on Earth.

That programme - with its famous face-to-face encounters with mountain gorillas in Rwanda - set the pattern for natural history documentaries in the decades that followed and helped establish him as one of the world's most authoritative voices on conservation.

The new show, Making Life on Earth: Attenborough's Greatest Adventure, goes into the stories behind the series and includes more footage of a baby gorilla climbing on the presenter and of a lioness hunting.

Reading from the diary he kept during filming, Attenborough recal...