13) In a 19th century French experiment by M. M. Biot and Arago a powerful lamp with good reflectors was placed on the summit of Desierto las Palmas in Spain and able to be seen all the way from Camprey on the Island of Iviza. Since the elevation of the two points were identical and the distance between covered nearly 100 miles, if Earth were a ball 25,000 miles in circumference, the light should have been more than 6600 feet, a mile and a quarter, below the line of sight!
On January 25th, 2016 Atlanta rapper B.o.B., who has self-identified as a member of the Flat Earth Society, tweeted a photograph of himself against a skyline, then tweeted a screenshot from Flat Earth Movement literature that proclaimed that Polaris (the North Star) can be seen 20° south of the Equator. Neil DeGrasse Tyson answered the rapper's question, writing "Polaris is gone by 1.5 deg S. Latitude. You’ve never been south of Earth’s Equator, or if so, you've never looked up."
Astronomers tell us that, in consequence of the Earth's "rotundity," the perpendicular walls of buildings are, nowhere, parallel, and that even the walls of houses on opposite sides of a street are not! But, since all observation fails to find any evidence of this want of parallelism which theory demands, the idea must be renounced as being absurd and in opposition to all well-known facts. This is a proof that the Earth is not a globe.