Below is the circumference of the earth, or the supposed distance measured around the earth in a perfect circle.
If you divide the circumference of the earth by 360, the number of degrees in a circle, you are left with 69.169444444 miles per degree of curvature. Thus each degree of the earth's circumference is 69.1694444 miles. (69, an interesting number)
Let us get from miles to feet.
5,280 feet per mile
69.1694444444 x 5280 feet is 365,214 feet
365,214 feet represents 1-degree of the earths curvature (365-days in a year?)
So every 1/360th of the earth's circumference, is a stretch of 365,214.6 feet.
To put that in perspective, that is 60,869 6-foot tall people lined up head to toe.
In meters, the number is 111,317.
That is the same as 15,840 feet, or 2,640-people who are six-feet tall lined up, head to toe. In theory, the 2,641st person, part of their body would be hidden from the human eye, and further more with each person until no longer seen.
Such an experiment could be conducted rather easily using proper measurement tools to put the argument to rest, is there curvature or not? I would love to see some of the flat earth believers put in the work. If you live in an area that is flat, for stretches of miles, like the middle of the United States, you can probably conduct a fairly accurate experiment.