2017-04-20

An explosion on Deepwater Horizon, an offshore rig in the Gulf of Mexico, resulted in the largest marine oil spill in history.

American racing driver Danica Patrick won the Indy Japan 300, becoming the first woman to win an IndyCar auto race.

Fernando Lugo became the first candidate not from the Colorado Party candidate to be elected President of Paraguay in 61 years.

An incomplete tunnel leading to the Nicoll Highway MRT station in Singapore collapsed, resulting in four deaths and the station's relocation.

Students Eric Harris and Dylan Klebold carried out a massacre at Columbine High School, killing 13 people before committing suicide.

Korean Air Lines Flight 902 was shot down after violating Soviet airspace and was forced to make an emergency landing.

Enoch Powell (pictured), a British Conservative member of Parliament, made a controversial speech in opposition to immigration and anti-discrimination legislation, resulting in his removal from the shadow cabinet.

South African Airways Flight 228 crashed shortly after take-off from Windhoek in South West Africa, resulting in 123 deaths.

Pierre Trudeau was sworn in as prime minister of Canada, succeeding Lester B. Pearson.

World War II: German and Italian forces began a large-scale counter-insurgency operation in occupied Yugoslavia.