Replica of the flagship of Columbus, . ... When Christopher Columbus proposed to reach India by sailing west from Spain, he too knew that the Earth was round. ... The Greek philosopher Erathosthenes went one step further and actually estimated how large the Earth was. ... Erathosthenes established that the direction of the noon Sun differed from the zenith by an angle that was 1/50 of the circle, that is, 7. 2 degrees, and from that he estimated the circumference of the Earth to be 250,000 stadia. ...