To summarize the podcast. Reddit user WhoTrulyKnowsRL

I went up to Denver Colorado, then went hiking at the Flatirons about 25 miles away. I had listened to a podcast on the hated topic of the flat earth.

At the Flatirons I stood at 8000 ft elevation, and took a picture of Denver 25 Miles and 6000 ft elevation. This means it has a drop of 416 ft curve downward due to curvature. Something not visible to the human eye.

But, the calculator that I found online calculates those figures to the Max visible horizon as 54.77 Miles. The picture does appear to match this, looking at the amount of land you could see behind the cityscape.

Next, I tried to see if we could potentially be able to see curvature to from high enough, like one a plane. Or from the pilots seat.