It's not that the earth is flat, its the "down" is not the down you have been taught. Our understanding of gravity and electromagnetism has given the wrong idea. Somewhere below the crust at the poles there is a north and south, at both poles. When you go forward, you don't travel down, but rather inward. Here is a more visual representation to help you understand. This is the reason we got involved in world war 2.

Research and understand instead of mocking.. it's not as silly as you may think.

Hitlers Nuclear Bell - https://en.wikipedia.org/wiki/Die_Glocke
The Real Atlantis - Where hitler went after "suicide" - https://en.wikipedia.org/wiki/Agartha
The mission to the pole to fight hitler, we were destroyed by UFOs with Nazi symbols - https://en.wikipedia.org/wiki/Operation_Highjump
The admiral who found agartha and also participated in highjump - https://en.wikipedia.org/wiki/Richard_E._Byrd
Supposed diary of Byrd claiming wooly mammoths - https://www.bibliotecapleyades.net/tierra_hueca/esp_tierra_hueca_2d.htm