David Cameron has condemned as "despicable and barbaric" the apparent slaughter of a second US journalist by Islamic State extremists - as it emerged that a British hostage is also under threat.
The U.S. State Department says it is "sickened" by a video that purports to show the beheading of U.S. journalist Steven Sotloff, adding that the intelligence community is working to authenticate the video. Rough Cut (no reporter narration).
They can tear the fabric of the universe asunder and destroy entire solar systems. Presenting 10 mind-bending facts about black holes.
Music = Invasion at Dawn by Gerrit Wunder and Dorothee Badent
10 Things You Didn't Know About YouTube
Everyone knows YouTube is one of the most popular websites on the internet, but here are other 10 things you might not know about the famous video sharing site.
10 Most Important Numbers In The World
They can be used to explain everyhing from melting ice cubes to the age of the universe. Presenting the 10 most important numbers in the world.
Music = Miami Clubhouse by Jason Pedder and Ben Ziapour
Mario wasn't always a plumber and he wasn't always called Mario. Presenting 10 awesome facts about Nintendo
Sources: Tech Radar, New Yorker Magazine, Nintendo, Official Nintendo Magazine, Guardian - UK, CNN, Business Insider, IGN, NY Times