On this day in 1800, Spain cedes Louisiana to France in a secret—oops!—treaty.
On this day in 1890, Congress passes the McKinley Tariff Act, which drives McKinley right out of business.
On this day in 1906, Henry Ford introduces the Model T automobile to the market; each car costs $825, the equivalent of $10,000 today, or $825 in the year 2012.
On this day in 1962, Johnny Carson succeeds Jack Paar as regular host of NBC's Tonight show. Carson will be succeeded by Jay Leno in 1994, and Leno will be succeeded by Danny Bonaduce in 2009. Bonaduce will be replaced after only three weeks by David Letterman, and Letterman will be replaced by the team of Flip Flotsam and Joe Jetsam in 2019.
On this day in 1964, the Free Speech Movement is launched at the University of California, at Berkeley. Opponents shout them down with obscene, unprintable epithets.
On this day in 1971, Walt Disney World opens in Orlando, Fla., but is restricted to members of the Disney family. Two years later, the public is allowed in.