Read about history and pick out an interesting one for us.
https://en.wikipedia.org/wiki/May_19
1780 – New England's Dark Day, an unusual darkening of the day sky was observed over the New England states and parts of Canada.
This is a strange one.
https://en.wikipedia.org/wiki/New_England%27s_Dark_Day
"The likely cause of the Dark Day was smoke from extensive forest fires, for which there is evidence from the time of the Dark Day. When a fire does not kill a tree and the tree later grows, scar marks are left in the growth rings.[14] This makes it possible to approximate the date of a past fire. Researchers examining tree rings and fire scars in trees in the area that is today occupied by Algonquin Provincial Park in Ontario, Canada, see evidence of a fire in 1780 and attribute the Dark Day to that."
1921 – The United States Congress passes the Emergency Quota Act establishing national quotas on immigration.
https://en.wikipedia.org/wiki/Emergency_Quota_Act
The Emergency Quota Act, also known as the Emergency Immigration Act of 1921, the Immigration Restriction Act of 1921, the Per Centum Law, and the Johnson Quota Act (ch. 8, 42 Stat. 5 of May 19, 1921) was actually formulated mainly in response to the large influx of Jews fleeing persecution in Eastern Europe and thus successfully restricted their immigration and that of other "undesirables" into the United States.
Although intended as temporary legislation, the Act "proved in the long run the most important turning-point in American immigration policy"[2] because it added two new features to American immigration law: numerical limits on immigration and the use of a quota system for establishing those limits. These limits came to be known as the National Origins Formula.
Something that's headline news in 2019!