There have been many times where people have posted images of buildings sinking below the horizon and flat earthers start making up laws of perspective that somehow make it work on a flat Earth. Here I will demonstrate how that doesn't work.
Look at this image:
There are many like it which show buildings sinking below the horizon, and I am using this particular one for demonstration purposes.
Look what happens when I add lines to represent the horizon and the estimated ground level for the buildings:
On a round Earth this makes perfect sense:
On a flat Earth it does make sense that the ground the buildings are on are below the horizon line, but the horizon clearly is in front of the buildings. In a flat Earth I don't see any way that this would be possible.
The horizon is clearly quite close, and in this case is closer then those buildings. Let's assume that light travels a finite distance through air and that causes the horizon:
Slight problem: this means you can't see the buildings at all and the horizon is below the base of the buildings in your perspective.
Many flat earthers believe that nearby waves can block buildings in the distance even if the observer is above them:
But that too doesn't work.
There is only one potential scenario I can think of where we can see on a flat Earth involving waves taller then the observer is high:
It requires that there are waves higher then the observer. This effect of buildings sinking below the horizon happens even when you are quite high up and at the tops of buildings. This means that there would have to be some pretty huge waves out there. This should give you an idea of how big they would have to be:
And on top of that, the size of the mega wave between you and the city would have to change based on the distance to the object you are observing. I don't think I have to explain why this idea is complete nonsense.
There is a way that it's possible though, and it requires the oceans to have a steady curve to them and for gravity to change directions to compensate. This would require that eventually the Earth would go around and reconnect with it's self forming a huge sphere. Wait a minute, that sounds familiar:
This model also has the added benefit of explaining many things like sunsets, the motion of the stars, the Antarctic midnight sun, how everyone always sees the same side of the Moon, and best of all it doesn't require an impossibly large conspiracy. The theory is already well developed, capable of making incredibly acurite predictions, and we even have photographic evidence that it's true.