<human>:  Who was the first person to think that the Earth was round?
<bot>: That would be the ancient Greek philosophers. The ancient Greeks believed that the Earth was flat, and that the sun revolved around it. However, the ancient Greek philosopher Thales of Miletus is often credited as the first person to think that the Earth was round. He was born in the year 625 BC, and died in the year 546 BC.