Breathing poison in the world's most polluted city
How the first selfie stick was mocked as a 'useless invention'
The strange afterlife of Einstein's brain
An elegant set of photos posted by a Tibetan couple have captured the attention of millions of Chinese social media users.
The filter bubble effect is limiting what news users of social media see about the General Election
When did the New York Times first explain pizza to its readers, and other news nuggets.
A county in China is punishing poorly-performing officials with military-style training camps.
The week's big numbers, visualised.
A collection of some of the best reads from the BBC News website this week.