Zeno of Elea was an ancient Greek philosopher who lived in the 5th century BC. He is best known for his paradoxes, which were used to challenge accepted ideas about space and time. He was a member of the Eleatic school of philosophy, which focused on the concept of being and the unity of all things. Zeno's most famous paradox is known as 'Achilles and the Tortoise, ' which states that if Achilles gives a tortoise a head start in a race, he will never be able to catch up to it. This paradox has been used to illustrate the concept of infinity.