Happy Something Something

I know there's some epochal event being celebrated today... but for the life of me I can't remember what it is. The Bolshevik murder of Tsar Nicholas II?

No, that's not right. The opening of the Tuskeegee Institute? The birth of the Crab Nebula? The ascension of the last Sultan of the Ottoman Empire?

Oh! Silly me, how could I possibly have been so mistaken. Happy 201st Anniversary of the French Occupation of Amsterdam, everyone! Cassez-vous, the Dutch!