A polymer note replaced the paper £20 note in the UK.
$10 billion was pledged to help fight climate change by Amazon's CEO, Jeff Bezos.
The United States had its first official COVID-19 related death.
US President Donald Trump was acquitted of impeachment charges by the US Senate.
The United Kingdom left the European Union, also known as 'Brexit.'
Coronavirus was declared a Public Health Emergency of International Concern by the World Health Organization (WHO).
A helicopter carrying nine people, including Kobe Bryant and his daughter, crashed in California with no survivors.
The world's largest twin-engine airliner completed its first trip.
One hundred million people were placed in lockdown in Wuhan, China, amid the COVID-19 outbreak.
A meteorite that hit Australia 2.2 billion years ago was announced as Earth's oldest recognized meteorite impact structure.
The trial phase of former US President Donald Trump's first impeachment began.
A meteorite that landed in Australia in the 1960s revealed stardust up to 7 billion years old.
Diego, a 100-year-old tortoise, was retired from a breeding program after fathering 800+ children.
Justin Bieber posted on Instagram that he has Lyme disease, a bacterial illness spread by ticks.
Jesse initiated the 9to5buzz, a concise online platform providing information on current events in history.
A couple got married at their local Dunkin' Donuts after breaking up their relationship at the same Dunkin' Donuts 25 years prior.
The US House of Representatives voted to impeach President Donald Trump for abuse of power (230 votes to 197) and obstruction of Congress (229 votes to 198).
Australia recorded its hottest day ever with an average temperature of 105°F across the country.
Mariah Carey's single 'All I Want for Christmas Is You' reached number one, 25 years after its release.
The longest ever United Nations climate talk ended.
The deepest point of land was identified.
Climate activist Greta Thunberg was named Time magazine's Person of the Year.
The World Health Organization announced that 142,000 people died of measles around the world in 2018, nearly 20,000 more than in 2017.
Speaker of the US House of Representatives, Nancy Pelosi, announced articles of impeachment against President Donald Trump would be drawn up for the abuse of power.
North American migratory birds getting smaller, their wings wider due to climate change according to study by University of Michigan published in journal 'Ecology Letters'.
The 70th anniversary of NATO was marked by a gathering in London of world leaders, followed by a reception by Elizabeth II at Buckingham Palace.
Spotify announced Drake as the most-streamed star of the 2010s with 28 billion streams, and Ed Sheeran's 'Shape Of You' as the most-streamed track with 2.4 billion streams.
Earliest traceable patient, a 55-year-old man, develops symptoms of a novel coronavirus (COVID-19) in Wuhan, China.
A wooden relic thought to be from Jesus's manger was returned to Bethlehem.
The 400th anniversary of the end of the Transatlantic Slave Trade was celebrated with the 'Year of Return' in Ghana.
The world's largest luxury goods corporation, Louis Vuitton (LVMH), bought jeweler Tiffany & Co. for $16.2 billion.
Taylor Swift won six awards at the American Music Awards, including Artist of the Year and Artist of the Decade.
Elon Musk revealed Tesla's first electric cyber truck with shatterproof windows.
Snake fossils found in Rio Negro Province, Argentina, showed snakes with hind legs that lived over 70 million years ago.
Oxford Dictionaries declared 'climate emergency' as the word of the year for 2019.
The Brazilian Space Agency announced that the country's Amazon rainforest had suffered its biggest spike in deforestation in over a decade.
A 55-year-old man became the first known person to contract COVID-19.
The city of Havana, Cuba, celebrated its 500th birthday.
The Disney+ streaming service was launched.
Iran claimed to have found over 50 billion barrels of oil in the country's Khuzestan province.
462 non-violent inmates were released from Oklahoma prisons in the largest commutation in American history.
Climate Control reported that rising sea levels would 'erase' many coastal cities by as early as 2050.
Forty-two people were buried alive in a landslide in Bafoussam, Cameroon.
Actor Wes Studi received the Governor's Award Oscar for Lifetime Acting Achievement, making him the first Native American to do so.
Major Australian newspapers blacked out their front pages in protest against press restrictions on printing whistleblower stories.
The oldest natural pearl discovered off the Abu Dhabi coast was estimated to be 8,000 years old.
The first all-female spacewalk took place.
Lana Del Rey's song 'Video Games' was named song of the decade at the Q Awards in London.
The Netflix movie 'Bird Box' and the TV series 'Stranger Things' was reported to be Netflix's most popular for 2019.
A camera in London Zoo became the first camera to take selfies powered by plants.
