The Treaty of Guadalupe Hidalgo, ending the Mexican War, was signed. In the treaty, Mexico ceded to the United States a huge portion of what is today the American West and Southwest, including California and New Mexico.
The Cardiff Giant was revealed to be a hoax.
The National League of Professional Baseball Clubs was formed.
The first gathering at Gobbler's Knob in Punxsatawney, Pa. to wait for the groundhog's shadow occurred.
James Joyce's Ulysses was published.
The Abscam scandal was revealed.