The life of Euclid is not well documented, but it is known that he lived in Athens, Greece for a time. He is also known to have taught in Alexandria, Egypt.
The first record of Euclid's life is as a student at Plato's school in Athens. Euclid also taught in Alexandria, and it was there that he published his most famous work, "The Elements." There is some belief that Euclid was born in Megara, but this may be a confusion with a philosopher named Euclid who was born about 100 years earlier.
A theory exists, advanced by historian Jean Itard, that Euclid was actually a fictional persona created by a team of mathematicians in Alexandria who were responsible for his work.