earth is round and i know (know not believe) that because all evidence say that, from satellite images to circumnavigation trips (trips that traveled round the world) 

a list of people who are certain that earth is flat

1- Pythagoras

2- Plato

3- Aristotle

4- Me

5- every real scientist 

6- all of the Pythagoreans

7- You after you read this

8-  Bill nye (the science guy)

9- Elon musk

10- neil deGrasse tyson