On July 21

People returning from anti-extradition bill protests were attacked (pictured) by suspected triad members in Yuen Long, Hong Kong, leaving 45 people injured.

Nour Ahmad Nikbakht, an Iranian diplomat in Yemen, was kidnapped by al-Qaeda militants and held hostage for the next two years.

Harry Potter and the Deathly Hallows, the final book in the popular Harry Potter series by J. K. Rowling, was released and sold 15 million copies in its first 24 hours, making it the fastest-selling book in history.

The Taiwanese military ordered the deportation of dozens of illegal immigrants from mainland China in sealed boat holds, causing 25 deaths due to suffocation.

Libyan forces carried out a raid at Sallum, sparking a four-day war with Egypt.

The Troubles: The Provisional Irish Republican Army detonated twenty-two bombs throughout Belfast, Northern Ireland.

Sirimavo Bandaranaike (pictured) was sworn in as prime minister of Ceylon, becoming the world's first democratically elected female head of government.

The inaugural International Mathematical Olympiad, the leading mathematical competition for pre-university students, began in Romania.

An earthquake registering 7.3 Mw struck the southern San Joaquin Valley in California, causing 12 deaths and an estimated $60 million in property damage.

After weeks of unrest, rioters lynched Bolivian president Gualberto Villarroel, desecrating and hanging his corpse in the streets of La Paz.

American high school biology teacher John T. Scopes was found guilty of violating Tennessee's Butler Act by teaching evolution in class.

World War I: An Imperial German Navy U-boat opened fire on a small convoy of barges and defending aircraft near the American town of Orleans, Massachusetts.

Much of central Pittsburgh, Pennsylvania, was burned and looted during the Great Railroad Strike of 1877.

Unrepresented labourers revolted and violently took over the government of the Republic of Florence (depicted), demanding that they be granted political office.

Louis III, Holy Roman Emperor, was captured and blinded during his attempt to restore Carolingian power over Italy by King Berengar I.

Paulinus was consecrated as the first bishop of York by Justus, the archbishop of Canterbury.

A large earthquake occurred near Crete, triggering a tsunami, and causing widespread destruction around the eastern Mediterranean region.

Pope Pontian began his pontificate, succeeding Urban I.