Original route of the Circle Line (grey) following Nicoll Highway (pink), and the realigned route (orange)

The Nicoll Highway collapse occurred in Singapore on 20 April 2004 when a Mass Rapid Transit tunnel construction site caved in near the highway next to the Merdeka Bridge. Four workers were killed and three were injured, delaying the construction of the Circle Line. The collapse was caused by a poorly designed strut-waler support system, a lack of monitoring and proper management of data caused by human error, and organisational failures of the construction contractors and the Land Transport Authority. Following the incident, the collapsed site was refilled, and the highway was reinstated and reopened to traffic on 4 December 2004. The authorities revised their construction safety measures to be above industry standards. The Circle Line tunnels were realigned (map pictured), with Nicoll Highway station rebuilt underneath Republic Avenue, to the south of the original site. The station and tunnels opened on 17 April 2010, three years later than planned. (Full article...)

Charles Holland

• ... that opera singer Charles Holland (pictured) spent much of his career in Europe as opportunities in classical music for African Americans were limited?
• ... that Thorpe's secluded hills provided refuge from Scottish raiders and English Civil War troops?
• ... that until the release of the documentary Predator: The Secret Scandal of J-Pop, sexual abuse claims involving record producer Johnny Kitagawa went widely unreported in Japanese media?
• ... that the damselfly relative Okanagrion is suggested to have eight species due to both alpha and beta diversity drivers?
• ... that even though a village said that it did not want a church, Indonesian politician Thoriqul Haq allocated land and money to build one along with a musalla?
• ... that the Eurovision Song Contest 1990, held in Yugoslavia, was the first Eurovision Song Contest to be held in the Balkans or in a socialist state?
• ... that librarian Amanda Jones won an award from the American Library Association for not backing down after receiving death threats for speaking out against book censorship?
• ... that a committee of Chinese compatriots of all circles from Hong Kong Island and Kowloon struggled against what they viewed as persecution by the British authorities in Hong Kong?

Flooding in Bahrain

• Flooding (pictured) in the Arab Gulf states leaves more than thirty people dead.
• The historic Børsen in Copenhagen, Denmark, is severely damaged by a fire.
• A knife attack in Sydney, Australia, leaves seven people dead.
• In retaliation for an Israeli airstrike on the Iranian consulate in Damascus, Iran conducts missile and drone strikes against Israel.
• In the South Korean legislative election, the Democratic Party–led opposition alliance increases its majority in parliament.

April 20: First day of Ridván (Baháʼí Faith, 2024); 420 (cannabis culture)

Vädersolstavlan

• 1535 – Sun dogs were observed over Stockholm, Sweden, inspiring the painting Vädersolstavlan (depicted), the oldest coloured depiction of the city.
• 1818 – Four days after the Court of King's Bench upheld an English murder suspect's right to a trial by battle in Ashford v Thornton, the plaintiff declined to fight, allowing the defendant to go free.
• 1942 – World War II: German and Italian forces began a large-scale counter-insurgency operation in occupied Yugoslavia.
• 1968 – South African Airways Flight 228 crashed shortly after take-off from Windhoek in South West Africa, resulting in 123 deaths.