A battle between rival groups at a prison near Monterrey in northern Mexico leaves 52 people dead and 12 injured, state officials say.
Nato is sending ships to deter people-smugglers from taking migrants from Turkey to Greece, in its first intervention in Europe's migrant crisis.
For the first time, scientists have detected tiny, rhythmic distortions in space and time - gravitational waves - predicted by Einstein 100 years ago.
The Cultural Revolution and the cult of the mango
The history of Thailand's current craze
How one Iranian city marked a revolutionary anniversary
US voters on what this election says about their country
Iran debates harassment after newsreader puts recording online
Music composed for feline friends
Why do some animals stay faithful?
What 7 vital things did Dad's Army teach us?