As Barack Obama prepares to leave office on January 20, here are nine things his presidency may be remembered for:

- Making history -

Stung by years of failure to stop Syria's bloodshed, the United States is now but a bystander to the civil war as President Barack Obama leaves office.

Secretary of State John Kerry still is speaking sporadically with Russian, Turkish and Arab foreign ministers about cease-fire efforts, and there are occasional consultations with the opposition. But less than two weeks before Donald Trump's presidency begins, the outgoing administration is no longer even claiming to play the leading part in the peace mediation that it spearheaded unsuccessfully for years. Formal contacts with Russia and others in Geneva, the main meeting point for the U.S.-led diplomacy, have ended.

U.S. Gulf allies are looking at Donald Trump to tilt Washington in their favour, analysts say, but fear a dangerous void if the incoming president goes so far as to tear up the Iran nuclear deal.

The U.S. and Russia have become embroiled in a Cold-War-style diplomatic spat over alleged cyberattacks Washington believes were carried out by Moscow in an attempt to skew the U.S. election.

The decades-old Israel-Palestinian conflict has returned to the spotlight after a U.N. resolution condemning Israeli settlements and a major speech by U.S. Secretary of State John Kerry.

Midnight means lights out in Syria's Aleppo: as the clock strikes 12, overworked power generators shut off across the city, plunging war-ravaged neighbourhoods and heritage sites into darkness.

After finding possible survivors and victim remains, the first priority of air crash investigators is to locate the black boxes, a duo of data recorders that can hold vital clues on why an aircraft went down.

Under different circumstances, Syrian President Bashar Assad's capture of Aleppo would project an aura of invincibility. He has survived nearly six years of revolt.

Instead, it has underscored his dependence on outside powers.

Nobody comes to Sesto San Giovanni by chance, say the residents of this dreary working-class Milan suburb where police caught up with Berlin market attack suspect Anis Amri.

So why, Italy wonders, did Europe's most wanted man end up here? 

On a rocky hill overlooking the Arabian Sea in the city of Aden sits the palace of Yemen's internationally recognized president. It's one of the few safe places in the country for him and his government, protected by troops at the gates, artillery and truck-mounted machine guns in the surrounding mountains and ships at sea.

The rest of the southern city remains unstable. Only a 10 minute drive from the palace, a suicide bomber struck days ago at the Sawlaban military base, killing 52 soldiers. It was the fourth time militants have hit the base in the past six months. The last strike was only about a week earlier. All told, the attacks have killed more than 180 people.