On this day, December 20, in 1898, President Emilio Aguinaldo ordered the commemoration of the day of Rizal’s death. This is the first decree about Rizal Day.
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 1999, Macau became a special administrative region of China, formerly owned by Portugal, and only returned to China in 1987.
https://www.britannica.com/on-this-day/December-20
On this day in 1879, Thomas Edison demonstrated his incandescent light invention to a select crowd in Menlo Park, New Jersey. He finished the invention here on Oct 21, 1879, after 13 months of work.
https://www.todayinsci.com/12/12_20.htm
December 20 is International Human Solidarity Day.
You may want to read: