On this day, April 4, in 1975 former senator Benigno Aquino Jr started a hunger strike to protest the way he was tried.
The official calendar of the Republic of the Philippines: an almanac of Philippine commemorations enlivened with illustrations and information. –Manila: Presidential Communications Development and Strategic Planning Office, [2014].
On this day in 1968, James Earl Ray assassinated Martin Luther King Jr. in Memphis, Tennessee while he was showing support for a city workers’ strike.
https://www.britannica.com/on-this-day/April-4
On this day in 1983, the space shuttle Challenger launched its first flight. It blew up in the air on the tenth flight in 1986.
https://todayinsci.com/4/4_04.htm
Today April 4 is Holy Tuesday.