1521: Spanish conquistadors led by Hernán Cortés capture Aztec Emperor Cuauhtémoc in Tenochtitlan, bringing the Aztec Empire to an end

1536: Buddhist monks from Kyoto’s Enryaku-ji Temple set fire to 21 Nichiren temples throughout Kyoto in the Tenbun Hokke Disturbance (Traditional Japanese date: July 27, 1536)

1642: Dutch astronomer Christiaan Huygens discovers Mars’s southern polar cap

1788: Prussia joins the Anglo-Dutch alliance to form the Triple Alliance to prevent the spread of the Russo-Swedish War of 1788-90

1937: Second Sino-Japanese War: Japanese forces start the Battle of Shanghai, a three-month conflict involving over one million troops

1942: The Manhattan Project commences under the direction of US General Leslie Groves with the aim of developing an atomic bomb

Source: Onthisday.com