Dammit Dok! Had this one slated for your post!
1846 - Commodore John D. Sloat lands at Monterey and claims California for U.S.
Protestors immediately materialize onshore and demand the warship leave.
Oh .... and ....
1847 - Marine Brigade leads U.S. forces that storm Chapultepec Castle near Mexico City, inspiring one line of the Marine Hymn "We kicked us some Mexican arse!" (which was later rewritten).