Horizon: Do You Know What Time It Is? is no longer available. Programmes are available for a limited number of days after broadcast. Why?
Horizon investigates speech, a phenomenon unique to humans, which remains a mystery...
What was there before the Big Bang? Black holes could hold the answer.
Three people with untreatable conditions see if, within their lifetime, they can... (R)
The search for answers to one of science's greatest mysteries: how do we know wh... (R)
Addiction expert John Marsden explores our relationship with alcohol. (R)
Chris Packham and Kate Humble share their adventures in a wildlife-rich cider or... (R)
Martin Hughes-Games chairs as the Autumnwatch presenters answer questions. (R)
Chris and Kate say goodbye to the summer's migrants and hello to the autumn arri... (R)
Martin Hughes-Games chairs as the Autumnwatch presenters answer audience questio... (R)
A look at how animals and plants go to extremes to give themselves a chance to b... (R)
Martin Hughes-Games chairs as the Autumnwatch presenters answer audience questio... (R)
Chris and Kate are at a wildlife hospital helping to care for sick and injured a... (R)
A look at the strategies used by reptiles and amphibians to conquer their shortc... (R)
Chris Packham and Kate Humble are in north Norfolk to witness the 'knot spectacl... (R)
Martin Hughes-Games chairs as the Autumnwatch presenters answer audience questio... (R)
Ray explores Canada's vast Boreal Forest and unlocks the secrets of this forgott... (R)
How mammals dominate the planet through having warm blood and by caring for thei... (R)
Jimmy tries to discover what really goes into supermarket sandwiches. (R)
A portrait of the lives of black bears in northern Minnesota, with biologist Lyn... (R)
Chris Packham and Kate Humble are in Gloucestershire for Halloween week.
Martin Hughes-Games chairs as the Autumnwatch presenters answer audience questions.
Ray tells the story of the British fur trade company that opened up Canada.
The nature documentary looks at fish as they dominate the planet's waters.
Jimmy tries to discover what happens to milk before it arrives on the supermarket s...