Cities usually come at the price of green space. Since prehistoric times, humans have busily cleared forests to make way for settlements. But increasingly, greenery has been edging its way back into modern urban landscapes, and for good reason. Vegetation helps cities become better habitats for wildlife and for people, and it helps to make city air safer.
The signs and impacts of global heating are speeding up, the latest science on climate change, published ahead of key UN talks in New York, says.
Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.