For many people, the word "ancient" simply means old-fashioned. But that's not quite right. Many ideas and ways of life that came from ancient Greece a few thousand years ago are still used today. It was the ancient Greeks who gave us libraries, democracy, and even the modern alphabet. The Greeks helped to shape the world in which we live. Here are some of their most famous people. Socrates Socrates was an ancient Greek philosopher. A philosopher is someone who thinks about the world and asks big questions. Socrates is famous for inventing what is called the Socratic method. This is a special way of teaching. Instead of talking the whole time, teachers ask students questions. That way, students learn how to think through problems. Socrates did not write his ideas down. We know about his life thanks to his student, Plato. Plato Plato was born about 2,400 years ago. He was a philosopher and writer. He wrote many books. One of his most famous books is "The Republic." In this book, Plato writes about fairness and happiness. George Washington and other Founding Fathers of the United States all knew about Plato's ideas. Aristotle One of Plato's students was a man named Aristotle. He was one of the greatest philosophers of all time. Aristotle thought about the meaning of life and how to treat others. He was also very curious. He studied animals and labeled them in different groups. Animal scientists today still follow some of his ideas. Alexander the Great Alexander the Great was the ruler of Macedon, a kingdom in ancient Greece. He lived more than 2,300 years ago. He fought in his first war when he was 18 years old. He was a brilliant leader. Alexander was able to create a huge empire. His empire reached as far as India. Pericles Pericles lived in the city of Athens. This was one of the most powerful cities in ancient Greece. Pericles was a leader and general. He did much to help Athenian culture. He helped pay to build the Parthenon. This is a temple dedicated to the goddess Athena. The Parthenon still stands today. Pythagoras Pythagoras was a Greek mathematician. The Pythagorean theorem is a famous math formula. It is used to find the area of a right triangle. It was named after Pythagoras. Hippocrates Hippocrates was very important for medicine. He was an ancient Greek doctor. He said people should exercise and eat healthy foods. Hippocrates is known for what is called the Hippocratic oath. It is a moral code or promises that doctors must follow. The most famous part is "Do no harm." These Greeks lived thousands of years before us. Their ways and ideas are still important today. They helped to build the world in which we live.