The gamma ray burst GRB 090423 is observed for 10 seconds. The event signals the most distant object of any kind and also the oldest known object in the universe.

Beijing closes all schools for two weeks because of the SARS virus.

Omaria massacre in Algeria: 42 villagers are killed.

Eritreans vote overwhelmingly for independence from Ethiopia in a United Nations-monitored referendum.

Namibia becomes the 160th member of the United Nations and the 50th member of the Commonwealth of Nations.

28 construction workers die when the L'Ambiance Plaza apartment building collapses while under construction in Bridgeport, Connecticut.

Coca-Cola changes its formula and releases New Coke. The response is overwhelmingly negative, and the original formula is back on the market in less than 3 months.

Vietnam War: Student protesters at Columbia University in New York City take over administration buildings and shut down the university.

Soviet space program: Soyuz 1 (Russian: Союз 1, Union 1) was a manned spaceflight, Launched into orbit carrying cosmonaut Colonel Vladimir Komarov.

Algiers putsch by French generals.

The Canadian Labour Congress is formed by the merger of the Trades and Labour Congress of Canada and the Canadian Congress of Labour.

Chinese Civil War: Establishment of the People's Liberation Army Navy.

1948 Arab-Israeli War: Haifa, the major port of Palestine, is captured from Arab forces.

World War II: Baedeker Blitz

World War II: The Greek government and King George II evacuate Athens before the invading Wehrmacht.

The Rhythm Night Club fire at a dance hall in Natchez, Mississippi, kills 198 people.

The Polish Constitution of 1935 is adopted.

The 153-year old De Adriaan Windmill in Haarlem, Netherlands burns down.

Turkey Türkiye becomes the first country to celebrate Children's Day as a national holiday.

The national council in Turkey denounces the government of Sultan Mehmed VI and announces a temporary constitution.

The Grand National Assembly of Turkey TBMM is founded in Ankara.

Theodore Roosevelt made his The Man in the Arena speech.

The Second Serbian Uprising - a second phase of the national revolution of the Serbs against the Ottoman Empire, erupts shortly after the annexation of the country to the Ottoman Empire.

King Charles II of England, Scotland and Ireland is crowned in Westminster Abbey.

Treaty of Oliwa is established between Sweden and Poland.

The first public school in the United States, Boston Latin School, is founded in Boston, Massachusetts.

William Shakespeare's ''The Merry Wives of Windsor'' is first performed, with Queen Elizabeth I in attendance.

Battle of Villalar: King Charles I of Spain defeats the Comuneros.

The founding of the Order of the Garter by King Edward III is announced on St George's Day.

Estonia: St. George's Night Uprising.

Ferdinand III of Castile conquers Cáceres.

Battle of Clontarf: Brian Boru defeats Viking invaders, but is killed in battle.