A series of high tension power towers carry electrical cables over Lake Pontchartrain in the U.S. state of Louisiana. The towers extend over a length of 25 km in a perfectly straight line and are all the same height. From an adjoining freeway, you can see the towers all in a line, with the towers in the distance clearly following the curvature of the Earth, as their pylons disappear beneath the horizon.
Many more photos, videos, and data are available on the Metabunk.org page “Soundly Proving the Curvature of the Earth at Lake Pontchartrain” where, of course, the Flat Earth contingent weigh in with their “analyses” of the “illusion”.