The president was acquitted, while the Democrats' Iowa caucuses ended in chaos. He also delivered a barnstorming State of the Union address. Also in the programme: locusts in Africa; the dead doctor who's shaken the Chinese leadership; the price of the battle between logging and butterflies in Mexico; and how do liberal democracies cope with terror prisoners determined to attack after their release. (Picture: President Trump holding a newspaper with the headline Trump acquitted. Credit: Reuters)