From the first cases in central China to hopes of a vaccine a year later, here are a dozen key developments in the spread and subsequent fight against COVID-19.
On Dec. 31, 2019, the World Health Organization (WHO) is alerted to a cluster of pneumonia cases "of unknown cause" in the central Chinese city of Wuhan.
On Jan. 7, 2020 a new coronavirus is identified. Four days later China announces its first death in Wuhan from an illness which will be named COVID-19.
Wuhan cut off
On Jan. 23 Wuhan is placed under quarantine and cut off from the world. Countries start to repatriate their citizens from China.
On Feb. 15 France reports the first death confirmed outside Asia, a Chinese tourist.
By March 6, more than 100,000 cases have been recorded around the world.
Northern Italy is locked down, quickly followed by the rest of the country.
On March 11, the WHO says COVID-19 is a pandemic.
Global stock markets crash. Governments and central banks roll out massive economic support measures.
Europe in lockdown
Spain (March 14) and France (March 17) order their populations to stay at home. Germany and Britain say people should avoid all social contact. The 27-nation European Union closes its external borders.
On March 24, the Tokyo summer Olympics scheduled for July 2020 are put off to the next year.
The next day the United Nations warns that the pandemic is "threatening the whole of humanity".
Half of world confined
Lockdown measures are enforced all around the world.
On April 2 more than 3.9 billion people -- half of the world's population -- are forced or called on to confine themselves, according to an AFP count. The same day the threshold of one million cases is crossed.
British Prime Minister Boris Johnson is infected and ends up in intensive care.
Economy on its knees
On April 29 the battered U.S. aircraft manufacturer Boeing slashes 16,000 jobs.
Many other groups including airlines and car manufacturers follow.
Backed by U.S. President Donald Trump as a potential treatment for COVID-19, malaria drug hydroxychloroquine is judged to have no benefit in a study published in The Lancet on May 22.
The study is retracted due to problems with the data but on June 5 a British research group also concludes that the medicine did not help COVID-19 patients at all.
Surge in Latin America
By June 7 the death toll reaches more than 400,000.
The surge of cases and deaths in Latin America causes concern.
Brazil becomes the country with the second biggest death toll after the United States. Its president Jair Bolsonaro calls it a "little flu", before himself becoming infected. Fellow COVID-19 skeptic Donald Trump will also get it.
Masks and anti-masks
With cases on the increase, several European countries make mask-wearing compulsory on public transport, in schools and shops, and on the street, starting with the Czech Republic on March 18.
Anti-mask demonstrations are organized in Berlin, London, Paris, and Rome.
The grim milestone of a million deaths worldwide is passed on Sept. 28. In October infections start to spiral in Europe, where many countries order new lockdowns and curfews.
The pandemic also picks up pace in the U.S., where its handling has become a key issue in the presidential campaign.
On Nov. 9, US biotech giant Pfizer and its German partner BioNTech unveil positive results of a vaccine, as the number of official cases passes 50 million.
A week later a similar announcement comes from U.S. firm Moderna, with an AstraZeneca-Oxford University vaccine following fast behind. Authorities hope to begin vaccination campaigns at the end of the year in the U.S. and parts of Europe.