Fish have been filmed more than 8km down in the Mariana Trench - the deepest place on Earth.
The agency guarding the US president is too insular and must recruit its next head externally, a review prompted by a White House security breach says.
The cyber attack on Sony that forced a major film release to be pulled is being viewed as a national security matter, the White House says.
The European Union needs a "plan for years" towards Russia, Donald Tusk says, chairing his first summit as European Council president.
Shrinking the bubbles generated by ships could counteract the impact of climate change, a study suggests.
Microsoft has launched a test version of the Skype Translator which decodes conversations in Spanish and English in near real time.
Do you remember who said what from 2014?
The do-it-yourself electronics maker littleBits has released a "smart home" automation kit.
The BBC's Andrew Walker considers how big a problem global debt really is.
Did Vladimir Putin think high oil prices would last for ever?
Lord Sugar's adviser on The Apprentice Nick Hewer announces he is to leave the BBC One show after a decade.
The underground escape games taking Hungary by storm
BBC News spends a night on Norwich's SOS bus as peak Christmas Party season gets under way.
Why are people flocking to Hungary in order to try and escape from locked rooms?
Israel says a Palestinian effort to set a three-year deadline for it to end its occupation of Palestinian territories is a "gimmick".
Nasa's Orbiting Carbon Observatory produces its first global maps of carbon dioxide in Earth's atmosphere.
Nearly 250 prison officers are being bussed across the country to fill gaps at other jails because staff shortages are so acute this Christmas, according to leaked documents.
Russian President Vladimir Putin discussed the economy, Ukraine and his love life over the course of a three-hour news conference. Here are five things we learnt this year.
Nebraska and Oklahoma are asking the US Supreme Court to nullify a 2012 law that made marijuana legal in the US state of Colorado.
Both girls accused of stabbing a Wisconsin classmate in order to please an online fictional character are competent to stand trial, a judge says.