So, I was doing some flat-earth research for a colleague and I ran across some facts about

CN Tower that, among other things,

boasted about being able to see ~100 miles on a clear day (fact 12). This seemed fishy to me so I dusted off some triganometry and used arc cosine to find out how far you can see from the observation deck before the "round-earth" curves away.

**Given Values**Height of the observation deck:

1,135 feetGenerous height of eye level:

6 feetElevation of Toronto:

249 feetMean Radius of the Earth at sea level (lol) =

20,903,520 feeth = Height of observation deck + Generous height of eye level + Elevation of Toronto

R = Mean radius of the Earth (lol)

h= 1390 feet

R= 20,903,520 feet

**Formula**How far you can see if you were on a sphere = R*ACOS(R/(R+h))

How far you can see if you were on a sphere = 20925524.9*ACOS(20925524.9/(20925524.9+1390))

How far you can see if you were on a sphere = 241,057.18 feet

How far you can see if you were on a sphere = 45.65 miles

45.65 miles isn't 100 miles... not by half. The only possible way you can see landmarks 100 miles away, such as Niagara Falls as they boast, is if the earth is flat. They even make note to say that it can only be seen on a clear day! Or, exactly what you would expect to see on a flat-earth.