December 30 – On This Day - RealLife Debates

1922 – The Soviet Union is officially established, uniting Russia, Ukraine, Belarus, and Transcaucasian republics. (britannica.com)
1924 – Edwin Hubble announces the discovery of a Cepheid variable in the Andromeda Galaxy, providing evidence that the “spiral nebula” is actually another galaxy outside the Milky Way. (nasa.gov)
1965 – President Lyndon B. Johnson establishes the Great Society programs with the signing of the Social Security amendments, expanding Medicare and Medicaid in the United States. (ssa.gov)
1993 – Israel and the Vatican establish full diplomatic relations. (vatican.va)

LeBron James (born 1984) – American professional basketball player. (nba.com)
Tiger Woods (born 1975) – American professional golfer. (pgatour.com)
Ricky Martin (born 1971) – Puerto Rican singer and actor. (britannica.com)
Duncan Jones (born 1971) – British film director and screenwriter, son of David Bowie. (imdb.com)

Rizal Day (Philippines) — National holiday commemorating the execution of José Rizal, a national hero, in 1896. (gov.ph)
December 30 marks the end of the calendar year’s public observances in some countries and is often a day of reflection before New Year’s celebrations.