1520: Hernán Cortés and the Tlaxcalans defeat a numerically superior Aztec force in the Battle of Otumba in Mexico

1807: French Emperor Napoléon Bonaparte and Russian Tsar Alexander I meet on a raft in the middle of the Neman River and sign the first Treaty of Tilsit

1937: Japanese and Chinese troops clash at the Marco Polo Bridge near Beijing, beginning the Second Sino-Japanese War

1947: Alleged and disputed Roswell UFO incident

2005: Coordinated terrorist bomb blasts strike London’s public transport system during the morning rush hour, killing 52 and injuring 700

2005: Influenced by global Live 8 concerts, G8 leaders pledge to double 2004 levels of aid to Africa from US$25 to US$50 billion by the year 2010 and to drop the debt owed by 18 of the most heavily indebted poor countries. Results are mixed.

Source: Onthisday.com