On April 6

A bus carrying the Humboldt Broncos collided with a semi-truck, killing 16 and injuring 13.

The National Movement for the Liberation of Azawad unilaterally declared the region of Azawad independent from Mali.

Mexican drug war: Authorities discovered 59 bodies in clandestine mass graves linked to earlier bus hijackings in San Fernando, Tamaulipas.

Naxalite–Maoist insurgency: Insurgents from the Communist Party of India (Maoist) ambushed a Central Reserve Police Force convoy in Dantewada district, India, killing 76 officers.

Mass protests began across Moldova against the results of the parliamentary election.

An earthquake measuring 6.3 Mw struck near L'Aquila in the central Italian region of Abruzzo, killing 308 people and leaving more than 66,000 homeless.

Kurdish leader Jalal Talabani was elected by the National Assembly as the first non-Arab president of Iraq.

Lithuanian president Rolandas Paksas became the first European head of state to be removed from office by impeachment.

The aircraft carrying Rwandan president Juvénal Habyarimana and Burundian president Cyprien Ntaryamira was shot down in Kigali; the event became the catalyst for the Rwandan genocide.

ABBA won the Eurovision Song Contest representing Sweden with the song "Waterloo".

Four California Highway Patrol officers were killed in a shootout following a traffic stop in Newhall, north of Los Angeles.

Second World War: The Battle of Slater's Knoll on Bougainville Island concluded with a decisive victory for the Australian Army's 7th Brigade against the Imperial Japanese Army's 6th Division.

World War II: German forces invaded Greece and Yugoslavia.

World War II: The Luftwaffe began Operation Retribution, bombing the Yugoslav capital of Belgrade in retaliation for a coup d'état that overthrew the government that had signed the Tripartite Pact.

Varney Air Lines made its first commercial flight (flight covers pictured), later forming the basis of United Airlines.

Joseph Smith, Oliver Cowdery, David Whitmer and others formally organized the Church of Christ, starting the Latter Day Saint movement.

Peninsular War: After a three-week siege, the Anglo-Portuguese Army, under the Earl of Wellington, captured Badajoz, Spain, and forced the surrender of the French garrison.

Napoleonic Wars: British forces captured the French frigate Niémen in the Bay of Biscay.

John Jacob Astor founded the American Fur Company, the profits from which made him the first multi-millionaire in the United States.

American Revolutionary War: Ships of the Continental Navy unsuccessfully attempted to capture HMS Glasgow near Block Island.