Greece is a country in southeastern Europe, known in Greek as Hellas or Ellada, and consisting of a mainland and an archipelago of islands. Greece is the birthplace of Western philosophy (Socrates, Plato, and Aristotle), literature (Homer and Hesiod), mathematics (Pythagoras and Euclid), history (Herodotus), drama (Sophocles, Euripedes, and Aristophanes), the Olympic Games, and democracy. The concept of an atomic universe was first posited in Greece through the work of Democritus and Leucippus. The process of today's scientific method was first introduced through the work of Thales of Miletus and those who followed him. The Latin alphabet also comes from Greece, having been introduced to the region by the Phoenicians in the 8th century BCE, and early work in physics and engineering was pioneered by Archimedes, of the Greek colony of Syracuse, among others. Independence day is celebrated in Greece on 25 March 1821.