As President Trump takes office, Katty Kay in Washington and Christian Fraser in London report on the events that are shaping our world.

Tim finds the Whitby hotel where Dracula novelist Bram Stoker stayed, visits the seaside resort of Scarborough and arrives on the north Norfolk coast at night. Show more

Richard Fortey investigates why islands are laboratories of evolution. On Madagascar he discovers lemurs, the giraffe-necked weevil and the aye-aye. Show more

Series exploring the Celts. The first part looks at the origins of the ancient civilisation in the Alps of central Europe and the moment of first contact with the Romans. Show more

Simon Reeve explores Colombia at a pivotal point in its history. For 50 years, Colombia has been in the grip of a brutal civil war, but in late 2016, a peace deal was signed. Show more

Nobel laureate Sir Paul Nurse looks at what science can do to fix our bodies and extend our lives, and also whether it's right to use all the tools and techniques available. Show more

Horizon meets Dr Mary Schweitzer, who may have found traces of DNA within the fossilised bones of a Tyrannosaurus rex - a discovery that could revolutionise our understanding of these beasts. Show more

Series exploring the Celts. The first part looks at the origins of the ancient civilisation in the Alps of central Europe and the moment of first contact with the Romans. Show more

Richard Fortey investigates why islands are laboratories of evolution. On Madagascar he discovers lemurs, the giraffe-necked weevil and the aye-aye. Show more

A look at some of the stunning recent work of an exceptional generation of British architects born in the 1930s, led by Norman Foster and Richard Rogers. Show more