In this final episode we complete our journey, travelling back from the March equinox to the end of June. Kate Humble is in the Arctic at a place where spring arrives with a bang, whilst Helen Czerski chases a tornado to show how the earth's angle of tilt creates the most extreme weather on earth.

The film depicts the life and work of opera singer Maria Callas in her own words by using performances, TV interviews, home movies, family photographs, private letters and unpublished memoirs nearly all of which have never been shown to the public.
Maria by Callas reveals the essence of an extraordinary woman who rose from humble beginnings in New York City to become a glamorous international superstar and one of the greatest artists of all time. Her letters and unpublished memoirs are read by opera singer Joyce DiDonato. (Click CC for subtitles)

The world's shipping industry is facing a major challenge. If global shipping were a country it would be the sixth largest producer of greenhouse gas emissions. At current growth rates, if we do nothing, those emissions could double or even triple by 2050. But shipping companies and engineers are creating remarkable new machines to make their industry greener, using a resource that has moved man across the world’s oceans for thousands of years…Wind.

Bob Marley's universal appeal, impact on music history and role as a social and political prophet is both unique and unparalleled. Marley is the definitive life story of the musician, revolutionary, and legend, from his early days to his rise to international superstardom. Made with the support of the Marley family, the film features rare footage, incredible performances and revealing interviews those who knew him best.

Mars is filled with mysteries, Volcanoes 77 000 feet tall, Huge canyons, 3000 miles across and 6 miles deep, all kinds of interesting features. Awaiting you is some of the greatest scenery in our Solar System, on a world where water once ruled, then vanished into thin air. Where lost microbe empires may still survive underground. We've seen the postcards, and we do wish we were there.

Visit the planet most like Earth. There is a discussion of what life on Mars would be like and about the life forms that could've evolved there