The COVID-19 pandemic cast a long pall over 2020 but it also saw President Donald Trump beaten by Joe Biden in a tumultuous US election and the Black Lives Matter movement shake the world.

Here are some of the key events of the year:

Rampaging virus 

On January 11, less than two weeks after it alerts a cluster of pneumonia cases "of unknown cause", Beijing announces its first death from an illness which will become known as COVID-19.

By March a pandemic has been declared and a month later half of humanity is in lockdown as governments scramble to halt its spread.

Massive state aid programmes are rolled out to save jobs as the International Monetary Fund predicts recession, with the global economy shrinking by 4.4 per cent.

In November, drug companies announce positive results for several vaccines as a second wave of cases lashes the planet.

Within a month, the first shots are being given but by Christmas some 1.7 million people are dead, with the US the worst hit.

Iranian roulette 

The world holds its breath after top Iranian commander Qassem Soleimani is killed in a US drone strike in Iraq on January 3, days after pro-Iranian protesters storm the US embassy in Baghdad.

Iran retaliates by launching a volley of missiles at bases in Iraq housing US troops. The same day, it shoots down a Ukrainian passenger plane "in error" shortly after take off from Tehran, killing all 176 people on board.

Tensions mount again at the end of November when top Iranian nuclear scientist Mohsen Fakhrizadeh is assassinated, with Tehran blaming Israel.

Brexit endgame 

Britain becomes the first country to leave the European Union on January 31 following its 2016 Brexit referendum.

But crucial talks on future ties and trade with the bloc drag on for months, breaking deadline after deadline as negotiators try to avert a hard Brexit before a last-gasp deal on Christmas Eve.

While British Prime Minister Boris Johnson claims victory, Scotland's anti-Brexit leader Nicola Sturgeon says its future is "an independent, European nation".

US-Taliban accord

The US and the Taliban sign a deal in Doha on February 29, with all foreign forces to quit Afghanistan by May 2021 after nearly two decades of war.

Talks between the Afghan government and insurgents start in September, but fighting rages on as the Taliban launch attack after attack and a string of civil society figures are assassinated.

The Pentagon is due to pull 2,000 of 4,500 US soldiers out of the country by January 15, 2021.

George Floyd killed

The killing of George Floyd, a 46-year-old African American, by white police officers on May 25 in Minneapolis sparks protests across the US and inspires anti-racism rallies across the world.

The Black Lives Matter movement leads to a major debate about race and the toppling of statues of figures linked to slavery or colonisation.

Hong Kong clampdown 

In June, a year after a massive wave of demonstrations, China imposes a sweeping new security law on Hong Kong that opponents say undermines the semi-autonomous city's liberties, promised under its handover from Britain in 1997.

In December, three prominent Hong Kong activists are jailed including Joshua Wong.

Thais rise up 

Students spark protests in July that roll on for the rest of the year calling for a new constitution, reform of the monarchy and for Prime Minister Prayut Chan-O-Cha to resign.

Beirut blast 

A massive explosion on August 4 destroys much of Beirut's Port and devastates swathes of the capital, killing more than 200 and injuring at least 6,500.

The blast from a vast stockpile of ammonium nitrate fertiliser devastates an already teetering Lebanese economy and the credibility of its governing elite.

Fires and hurricanes 

Enormous bushfires rage across Australia in what becomes known as its "Black Summer" while in September San Francisco and other regions of the American West Coast wake to orange skies as the state's largest ever inferno breaks out.

In November, two hurricanes devastate Central America, leaving more than 200 dead.

The Navalny affair 

Kremlin critic Alexei Navalny is flown to Berlin in a medically induced coma after becoming violently ill after he boarded an internal flight to Moscow.

Tests reveal he was poisoned with the Soviet-era nerve agent Novichok. Navalny accuses Russian President Vladimir Putin of trying to kill him and later releases a recording where he appears to trick the alleged agent responsible into telling him the poison was put in his underpants.

Crisis in Belarus

Belarus strongman President Alexander Lukashenko's disputed victory in August 9 elections sparks four months of anti-government protests, centred on his main rival, political novice Svetlana Tikhanovskaya.

Opposition leaders are jailed or driven into exile.

Israel's new diplomatic ties

The United Arab Emirates and Bahrain normalise ties with Israel on September 15 as Palestinians condemn the move as a "stab in the back".

The next month Donald Trump announces that Sudan is joining them, while in another twist, Morocco "resumed relations" with Israel on December 10 in return for the US recognising its claim to Western Sahara.

China-US tensions 

2020 sees US-China relations nosedive, with Trump calling COVID-19 the "China virus" and saying Beijing is responsible for "a mass worldwide killing".

They also clash over the repression of Turkic speaking Uighur minority in the Chinese region of Xinjiang, as well as the national security law imposed on Hong Kong.

Biden beats Trump 

Deeply-divided Americans vote in record numbers in the November presidential election between outgoing Republican Donald Trump and Democrat Joe Biden.

After four days of nail biting, Biden takes the White House by 7 million votes. Trump cries fraud without evidence and has yet to concede defeat.

Nagorno-Karabakh 

Heavy fighting for the Armenian-populated region of Nagorno-Karabakh, which broke away from Azerbaijan after a war in the 1990s, goes on for 45 days.

Several thousand die before a Kremlin-brokered peace deal on November 9, with Armenians losing swathes of territory to Azerbaijani forces.

Ethiopia: Tigray conflict 

Ethiopian Prime Minister and Nobel Peace Prize winner Abiy Ahmed orders a military response to attacks on federal army camps in the dissident northern Tigray region.

The Tigray People's Liberation Front — which has dominated Ethiopian politics for nearly three decades — denies responsibility and says the reported attacks are a pretext for an "invasion".

Federal forces take the Tigrayan capital on November 28.