In its many centuries of existence, the Roman state evolved from a monarchy to a Classical Republic and then to an increasingly autocratic empire. Rome professionalized and expanded its military and created a system of government called res publica, the inspiration for modern republics. It achieved impressive technological and architectural feats, such as the construction of an extensive system of aqueducts and roads, as well as the construction of large monuments, palaces, and public facilities.

To eradicate those regarded as “enemies of the working class”, Stalin instituted the “Great Purge” in which over a million were imprisoned and at least 700,000 were executed from 1934 to 1939. In 1939 Stalin’s government signed a non-aggression pact with Nazi Germany. Germany ended the pact by invading the Soviet Union in 1941. The Soviet Red Army halted the German incursion and captured Berlin in 1945, ending World War II in Europe. Everyone thinks they know him, but who was Stalin, really?

Tesla explained the principles of the rotating magnetic field in an induction motor by demonstrating how to make a copper egg stand on end, using a device that he constructed known as the Egg of Columbus and introduced his new steam-powered oscillator AC generator.

Luther came to reject several teachings and practices of the Roman Catholic Church. He strongly disputed the Catholic view on indulgences. Luther proposed an academic discussion of the practice and efficacy of indulgences in his Ninety-five Theses. His refusal to renounce all his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the Pope and condemnation as an outlaw by the Holy Roman Emperor.

Caligula was born into the first ruling family of the Roman Empire, conventionally known as the Julio-Claudian dynasty. He is described as a noble and moderate emperor during the first six months of his rule. After this, the sources about the reign of Caligula focus upon his cruelty, sadism, extravagance, and sexual perversion, presenting him as an insane tyrant.

The Maya recorded their history and ritual knowledge in screen fold books, of which only three uncontested examples remain, the rest having been destroyed by the Spanish. The Maya developed a highly complex series of interlocking ritual calendars, and employed mathematics that included one of the earliest instances of the explicit zero in the world.