[bcRoundEarth]

Several years ago, I took a cruise from Miami to the Bahamas.  On the return trip, when our boat was about 30 miles away from Miami, the tops of the high rises became visible.  As we got closer, the city would rise up on the horizon until it was fully in view.

I'd like to Flat Earthers to explain how this could happen if the earth was indeed flat. 

If the Earth was truly flat, Miami would have been visible to us as soon as we set sail from Miami.  If there's nothing but a flat ocean surface in between us, then a city that is 181 miles away should be perfectly visible to us across a flat ocean.  And as we approach that city, it should be entirely visible to us as we approached.  The city would not be rising on the horizon as it does on a round earth.

[Roger G]

There have been various attempts to explain this and I have difficulty getting my head around them, but the latest one seems to be something like: as things become further away, the lines of perspective converge until we can no longer see the object in question as the perspective lines meet. Apparently, increasing our height of viewing simply widens the perspective lines so that we can see further. There seems to be no real answer to the fact that as something disappears from view we can't even see it with powerful telescopes or binoculars. As a sailor, I can confirm that once something drops over the horizon from eye level viewing, even my binoculars can't see it, but if I climb up the mast, I can, with or without binoculars. That can only be the case if the world is spherical.

Roger

[Tom Haws]

Somebody is going to have to do a LOT better job of explaining these lines of perspective and how they reveal only the very top of one building, followed successively by more and more buildings and parts of buildings.

[bcRoundEarth]

So in flat earth theory, when something is really far away it just becomes so tiny you can't see it?  Yeah, that's pretty flimsy because on a flat earth, the entirety of the object should be within view the entire time you approach it.  It would start as a small dot and then just get bigger and bigger and bigger.  The bottom of the object would be visible the entire time.

And this is an experiment that all flat earthers can experience for themselves.  Just drive toward any really tall mountain or get in a boat to ride away from the coast for about 30 miles.  The tall structure will rise from the horizon as you approach it.  And this is only possible if the earth is round.

[OrigamiBoy]

Yes, I highly suggest you watch vsause's video on this topic, he does a very good job explaining it.