Construction has begun on a giant observation tower in the heart of the Amazon basin in Brazil to monitor climate change.

The Chinese sturgeon, thought to have existed for more than 140 million years, is now on the brink of extinction, say local media.

Europe's Rosetta mission, which aims to land on a 4km-wide comet later this year, identifies what it thinks is the safest place to touch down.

A new study suggests that the contamination of drinking water by shale gas is due to faulty wells and not hydraulic fracturing.