Tim Harford pays tribute to a sporting legend - Sir Roger Bannister, the first person to run one mile in less than 4 minutes, who has died at the age of 88. After his record broke the ‘impossible’ psychological barrier, motivational speakers claimed the power of positive thinking soon helped dozens of runners to break the four-minute record, but what are the true figures? A BBC investigation has found that a fake blog and fake social media accounts were created to support the campaign of the former Brazilian president Dilma Rousseff in the 2010 election, which she won. As Brazilians look forward to a presidential election later in 2018, Juliana Gragnani reports on her investigation. Why do segregated groups still exist, especially “men only” clubs? With the current drive towards gender equality and movements such as MeToo and Time’s Up, aren’t such forms of socialising out of date? (Britain's Roger Bannister (centre) being congratulated by Chris Chataway after setting a new record of 3 minutes 59.4 seconds. On the left is Chris Brasher. Photo by Norman Potter / Getty Images)