Last in the series of David Attenborough's favourite Wildlife on One programmes.

In the deep caverns of the Borneo jungles huge mounds of guano seethe with golden cockroaches, while giant poisonous centipedes lurk on the walls. This is the home for the strangest of birds, swiftlets, which make their nests of spit and can fly in total darkness.

Alongside them are bats, who fall prey to underworld serpents. David Attenborough was visibly shocked as he entered the nightmarish world of the caves and he describes the film as "a portrait of a place that has what I can only describe as a horrid fascination".

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