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

The team looks at the trans-Neptunian objects - a vast number of strange, dark, icy worlds - which played a crucial role in the evolution of our solar system. Show more

Sam Willis looks at how castles survived into the Tudor era. But these strategic seats of power had to become palaces to impress monarchs such as Elizabeth I. Show more

Professor Danielle George uses five decades of BBC archive to find out how well disaster documentaries keep pace with scientific theories that advance every day. Show more

Historian Bettany Hughes presents a series of clues to show the legend of Atlantis was inspired by a real historical event, the greatest natural disaster of the ancient world. Show more

Professor Bruce Denardo attempts to prove if there is any truth behind the legend of the Bermuda Triangle, where many ships and planes have disappeared in mysterious circumstances. Show more

Dr Michael Mosley explores the bizarre and fascinating world of parasites by turning his body into a living laboratory and deliberately infesting himself with them. Show more

Writer and historian Michael Collins tells the story of the suburban garden and delivers a riposte to the urban intelligentsia who have spent a century sneering at the suburbs. Show more

Sam Willis looks at how castles survived into the Tudor era. But these strategic seats of power had to become palaces to impress monarchs such as Elizabeth I. Show more

Professor Danielle George uses five decades of BBC archive to find out how well disaster documentaries keep pace with scientific theories that advance every day. Show more