Aparently, I’ve conflated Level with Plumb, the walls cannot be parallel and plumb. Due to the curve, the center of gravity for the walls would require them to angle in slightly together or not be plumb.
We do have examples of buildings needing to account for the curvature of the earth.
One that comes to mind is The fountain at the Christian Science Mother Church in Boston…
It’s about a quarter mile long and the water flows evenly over the granite curbs along its entire perimeter. If it didn’t follow the earth’s curvature the water would all just spill over at the middle.
Im very surprised that noone here has mentioned the LHC in CERN Headquarters, Geneva, Switzerland. The LHC or Large Hadron Collider is so huge that it stretches across 2 countries (France and Switzerland) and stretches over a circumference of an impressive 17 miles (27 kilometers). It is so large that when building it they not only had to take into consideration the curvature of the LHC tunnel, but also the curvature of the earth.
