Notre part animale - Season 1 Episode 3

Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.

Dr Helen Czerski examines the world of sound waves.

Hannah Fry takes a spectacular look at the science of size by imagining a parallel world in which everything is made bigger or smaller.

TV's most-watched history series brings to life the compelling stories from our past that inform our understanding of the world today.