1/3 Exploring the largest animals that have ever lived on our planet- the great whales.
5/7 The story of the few extreme survivors who remain in the polar regions during winter.
Countryfile looks at the part the landscape has played in making scientific breakthroughs.
John Craven looks at the mineral Blue John hidden deep underground in the Peak District.
Celebrating 150 years of rail transportation with a look at India's rail network. (1975)
5/5 David Attenborough searches for one of the rarest animals of Madagascar, the indri. (1961)
4/5 David Attenborough finds ant lions, giant moths, mud wasps and lemurs. (1961)
1/5 David Attenborough searches for the strange creatures that inhabit Madagascar. (1961)