September 15 has seen democracies tested, battles turned, and cultural moments that echoed through generations.
Nazi Germany enacted the Nuremberg Laws, stripping German Jews of citizenship and prohibiting marriage between Jews and non-Jews. The laws institutionalized racial persecution and paved the way for the Holocaust.
The Royal Air Force inflicted devastating losses on the Luftwaffe in the climactic day of the Battle of Britain. Hitler postponed Operation Sea Lion, the planned invasion of Britain, indefinitely.
A bomb planted by Ku Klux Klan members killed four young Black girls at the 16th Street Baptist Church in Birmingham, Alabama. The atrocity horrified the nation and strengthened support for civil rights legislation.
Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica jointly declared independence from Spain. September 15 is celebrated as Independence Day across Central America.
British forces used tanks for the first time in combat during the Battle of Flers-Courcelette on the Somme. Though mechanically unreliable, the tank would revolutionize modern warfare.
Lehman Brothers filed the largest bankruptcy in US history, triggering a global financial crisis. The collapse sent shockwaves through the world economy and led to the Great Recession.
The world's first intercity passenger railway opened in England, connecting Liverpool and Manchester. The railway age had begun, transforming transportation, industry, and society.