A young student of Socrates by the name of Plato began teaching upon the death of Socrates. At the age of 30, Plato opened a school that would remain in operation for nearly nine centuries following his death.
Plato authored a book which he titled "The Republic," which outlined what he believed was the perfect government. Plato felt that a democracy was not the most effective form of government, because the lower classes of people could not be trusted. He felt that the higher classes, which were more educated, ought to be in charge of the government.
Who dares not speak his thoughts is a slave.
In 1783 Marquis d''Arlandes And Pilatre de Rozier became the first humans to fly. They used a hot air balloon, which kept them in the air for about 20 minutes.