All of our history is a lie. We have found other people with similar stories that they were taught the earth is flat in grade school. It appears the change over happened as late as the 1920's in the USA and even later in some other countries. Saying that we have known the earth is flat for 500 years is just a story that was inserted into the school text books in the 1980's! Eratosthenes the greek mathematician that supposedly did the famous sticks and shadows experiment 500 years ago and was able to figure out the alleged size of the alleged globe. The problem with that is is it's just a story. There is no mention of his experiment in any books until the 1980's when it was inserted into school text books. On top of that, the experiment doesn't prove the globe. It works perfectly on a flat earth!
https://www.youtube.com/watch?v=5Wt5qSwinIs&list=PLEzivhxtxgbv2hEBOrfkjHnRnpbH9hlXR&t=0s