Zeno of Elea was an ancient Greek philosopher who lived in the 5th century BCE. He is best known for his paradoxes, which were used to challenge accepted notions of space and time. He was a member of the Eleatic school of philosophy, which was founded by Parmenides. Zeno's most famous paradox is known as 'Achilles and the Tortoise, ' which states that Achilles can never overtake a tortoise in a race, no matter how fast he runs.