Offshore wind farms consist of a series of large turbines having a similar shape and size. In some cases, they are spread over a very large area of water. They are suitable landmarks where we can easily observe the effect of the curvature of the Earth.
If the turbines are far enough, the bottom parts will not be visible and the blades can look as if they are submerged. The phenomenon is only possible if Earth is a sphere.
The other day I was taking a break and flipping through local tv and some old show from the 70's or so was on. Don't know what it was but it was British--I think. They were investigating flat earth and how it sits on a turtle with elephants on its back. Their mission was to determine what sex the turtle was and they were arguing about why it matters. It was amusing.
