By Day: Historical Events on June 30th

The Spanish conquistador Hernán Cortés forces fight their way out of Tenochtitlan suffering severe loses as the Aztecs revolt against their rule. Many Spanish soldiers drowned in Lake Texcoco. The exit is known as the "Noche Triste" or “the Night of Sadness".

Einstein publishes his Special Theory of Relativity, which describes his revolutionary ideas about light, time and energy. He revisited the theory in a 1912 manuscript when he was asked to write several book chapters. The outbreak of World War I in 1914 delayed publication, and when the project resumed, Einstein considered this manuscript outdated and it was never published. More

Germany, Chancellor and Nazi leader Adolf Hitler orders a political purge intended to consolidate his power and alleviate the concerns of the German military about the role of Ernst Röhm and the Sturmabteilung (SA), the Nazis' paramilitary organization, known colloquially as "Brownshirts". The purge resulted in the killing of hundreds of Nazis whom he believed had the potential to become political enemies including Röhm. The actions became known as the "Night of the Long Knives". The bloody purge was followed by "Gleichschaltung" the process of Nazification by which Adolf Hitler — leader of the Nazi Party in Germany — successively established a system of totalitarian control and coordination over all aspects of German society "from the economy and trade associations to the media, culture and education" More

Democratic Republic of the Congo Independence Day

The three cosmonauts aboard the Soyuz 11, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, perished in space when the capsule depressurized during preparations for re-entry. They are the only humans known to have died in space. More

Deadline for ratification of the Equal Rights Amendment to the Constitution passes without the necessary votes