Pick a good one!
https://en.wikipedia.org/wiki/December_13
1938 – The Holocaust: The Neuengamme concentration camp opens in the Bergedorf district of Hamburg, Germany.
https://en.wikipedia.org/wiki/The_Holocaust
The Holocaust, also referred to as the Shoah,[b] was a genocide during World War II in which Nazi Germany, aided by its collaborators, systematically murdered some six million European Jews,[c] around two-thirds of the Jewish population of Europe,[d] between 1941 and 1945.[7] Jews were targeted for extermination as part of a larger event involving the persecution and murder of other groups, including in particular the Roma and "incurably sick",[8] as well as ethnic Poles and other Slavs, Soviet citizens, Soviet prisoners of war, political opponents, gay men and Jehovah's Witnesses, resulting in up to 17 million deaths overall.[e]
1971 – Norma McCorvey (Jane Roe) filled a law suit against Henry Wade, Dallas county attorney, in the Roe v. Wade case.
If the water's not too deep in the lake, you can wade across or roe.
I know, I know, that's terrible, and I apologize.
1949 – The Knesset votes to move the capital of Israel to Jerusalem.
Credit to Donald Trump for being the first President to recognize it. Also credit to Donald Trump for all the Palestinians killed in the ensuing riots.