Again, the TS-E 24mm f3.5L, demonstrating the effect of shifting (a.k.a. rise or fall).

This is the lens, unshifted and untilted, showing a nice bucolic scene.

NOTICE the edge of the barn seems tilted inward at the top, and the wall looks twisted. This is due to the fact that the sensor plane is pointed above the horizon, in order to center the silo in the frame. All lenses suffer from this perspective effect when pointed above (or below) the horizon, but wide angle lenses show more of it.