English: "Taken in Icod de Los Vinos, on the island of Tenerife in Spain, 400m above sea level. You can see the curvature of the horizon in this image, comparing the horizon line to the shape of a rail used as a rectilinear reference. This comparison makes it possible to overcome a potential deformation due to the camera lens, because such a deformation applies in the same way to the horizon line and to the guardrail. The horizon line touches the railing on the left and right of the image, but it rises above it in the center of the image. The horizon line therefore has a curvature that the railing does not have."

Compressed photo to show better the curvature of the horizon due to sphericity of Earth.

"The horizon appears flat because the curvature is too small when observed from near the Earth’s surface. However, in some cases, we can exaggerate the curve by taking photographs of the horizon and then magnifying the results vertically."

https://flatearth.ws/vertical-magnification