In History, Today on January 1

Croatia adopts the euro as its official currency and joins the Schengen Area, marking significant milestones in its European integration.

The United Kingdom officially completed its transition out of the European Union, marking the end of the Brexit process.

Croatia assumes the presidency of the Council of the European Union for the first time.

Jair Bolsonaro took office as the President of Brazil.

California legalized the sale of recreational cannabis.

Antonio Guterres began his term as the Secretary-General of the United Nations, succeeding Ban Ki-moon.

Lithuania adopted the euro as its official currency, joining the Eurozone as its 19th member.

Latvia adopted the euro as its official currency, becoming the 18th member of the Eurozone.

Ireland's Presidency of the Council of the European Union began.

Estonia adopts the Euro as its official currency, becoming the 17th member of the Eurozone.

Spain assumed the rotating presidency of the Council of the European Union, focusing on economic recovery and the implementation of the Lisbon Treaty.

Slovakia adopts the Euro as its official currency, becoming the 16th member of the Eurozone.

Cyprus and Malta adopted the euro as their official currency, further integrating into the Eurozone.

Bulgaria and Romania joined the European Union, expanding the EU to 27 member states.

The Republic of Ireland becomes the first country in the world to ban smoking in all workplaces, including bars and restaurants.

The euro currency was officially introduced in 12 European Union countries, marking a significant step in European economic integration.

The World Trade Organization (WTO) was established, taking over from the General Agreement on Tariffs and Trade (GATT), to facilitate international trade.

The North American Free Trade Agreement (NAFTA) officially came into effect, establishing a free-trade zone between the United States, Canada, and Mexico.

Czechoslovakia peacefully splits into the Czech Republic and Slovakia in what is known as the Velvet Divorce.

The United Kingdom, Ireland, and Denmark enter the European Economic Community, which later becomes the European Union.

Fidel Castro's forces overthrow the government of Cuban dictator Fulgencio Batista, marking the beginning of Castro's rule in Cuba.

The Treaty of Rome, establishing the European Economic Community (EEC), officially came into effect. This treaty laid the groundwork for what would eventually become the European Union.

The United Nations Declaration was signed by 26 nations pledging to uphold the principles of the Atlantic Charter and fight against the Axis powers during World War II.

Alcatraz Island became a United States federal prison, known for housing some of the most dangerous criminals.

The British Broadcasting Company became the British Broadcasting Corporation (BBC), a public corporation.

The Republic of China was officially established, marking the end of the Qing Dynasty.

New York City introduced the ball drop in Times Square for the first New Year's Eve celebration.

The first college football bowl game, the Rose Bowl, took place in Pasadena, California.

The Commonwealth of Australia is established as six colonies federate, marking the birth of modern Australia.

Ellis Island begins processing immigrants to the United States, becoming the nation's busiest immigrant inspection station.

Queen Victoria was proclaimed Empress of India as part of the British Empire's structural reformation.

The Emancipation Proclamation issued by President Abraham Lincoln takes effect, freeing slaves in Confederate states during the American Civil War.

The New York Herald proclaimed the start of the California Gold Rush, reporting large amounts of gold being discovered in California, spurring mass migration to the west.

The United Kingdom implements the Post Office Act, reforming its postal system and introducing a uniform Penny Post rate across the country.

The United Kingdom claims ownership of the Falkland Islands in the South Atlantic Ocean, which remains a point of contention between the UK and Argentina.

The importation of slaves into the United States was officially banned, in accordance with the Act Prohibiting Importation of Slaves enacted in 1807.

Haiti gains independence from France, becoming the first independent nation of Latin America and the Caribbean, and the first post-colonial independent black-led nation in the world.

The legislative union of Great Britain and Ireland is completed to form the United Kingdom of Great Britain and Ireland.

Albany became the capital of New York State, moving from Kingston.

The Times, a leading newspaper in the United Kingdom, was first published.

During the American Revolutionary War, General George Washington hoists the Grand Union Flag, the first national flag of the United States, at Prospect Hill.

The hymn that became famous as 'Amazing Grace' was first used to accompany a sermon led by John Newton in Olney, Buckinghamshire.

The first traveler's cheques, which can be used in 90 European cities, are issued by the London Credit Exchange Company.

Russia officially adopted the Julian calendar, moving the New Year from September 1 to January 1.

Portuguese explorers, led by Pedro Álvares Cabral, become the first Europeans to sail into Guanabara Bay, which they initially mistook for the mouth of a river. They named it Rio de Janeiro.

Charles II of Navarre dies and is succeeded by his son, Charles III, who becomes King of Navarre.

Michael VIII Palaiologos is proclaimed co-emperor of the Byzantine Empire.

The city of Lisbon is declared the capital of Portugal after its conquest from Moorish rule in 1147, solidifying its status in the medieval Kingdom of Portugal.

Edith of Wessex is crowned Queen of England following the conquest of England by her husband, King Harold II, who took the throne in 1066.

The Peace of God, a movement led by the Church to limit violence among feudal lords, was formally recognized in France, marking an early attempt at establishing peace and order in medieval Europe.

Prophet Muhammad and his followers set out to conquer Mecca, an event that would lead to the city's surrender and its conversion to Islam.

The last known gladiatorial games were held in Rome. These games were part of a long tradition of public spectacles in the Roman Empire.

The Roman Emperor Commodus was assassinated, leading to the Year of the Five Emperors, a period of civil war in the Roman Empire.

The Julian calendar, introduced by Julius Caesar, took effect for the first time. It was a reform of the Roman calendar and became the predominant calendar in the Roman world and later in most of Europe.