On Aug. 21, 1609, Galileo Galilei demonstrated his new telescope to a group of officials atop the Campanile in Venice.

In 1911, Leonardo da Vinci’s “Mona Lisa” was stolen from the Louvre Museum in Paris. (It was recovered two years later in Italy.)

In 1940, exiled Communist revolutionary Leon Trotsky died in a Mexican hospital.

In 1963, martial law was declared in South Vietnam, as police and army troops began a violent crackdown on Buddhist anti-government protesters.

In 1991, the hard-line coup against Soviet President Mikhail S. Gorbachev collapsed in the face of a popular uprising led by Russian Federation President Boris N. Yeltsin.

In 1995, ABC News settled a $10 billion libel suit by apologizing to Philip Morris for reporting the tobacco giant had manipulated the amount of nicotine in its cigarettes.