Alternative Universe Earth of the Week
This week's AUE: Earth #1700
"The world is flat," declared the greatest mathematical and cartological minds of the developing nations on Earth #1700. Until their middle ages, no credible information rose to prove them wrong. Sailors spoke of 'corners' of the world, fearsome zones where ship crews were stricken with the motion-sick sensation of rolling downhill for an hour straight, but the scientists didn't believe them.
That all changed in the seventeenth century, when Martin Tomas Del Velasco discovered a new continent, a vast land full of strange creatures and natives that spoke of 'falling mountains'. Later explorers, led by local guides, discovered a ridge that was a land-based 'corner of the world', later dubbed 'hinge lines' by cartographers.
Three men of the first party survived the tragedy that befell them. They stepped over the hinge line and then quickly back and fell, rolling on weathered rock in the distorted gravity.
Increasingly sophisticated surveying techniques revealed that Earth 1700 was an icosahedron.
In modern times, the hinge line zones are devoid of population, but the planet's amusement parks all located there.