Alleged history of sleep cycles based on geography, culture and seasons

https://m.youtube.com/watch?v=zMTnxlAv9mw

Far from the equator when night hours are long two sleep phases with a break in the middle which became one longer sleep phase after artificial lighting and the industrial revolution

Near the equator - One sleep phase

Ignores Siestas in sleep cycles in Mexico which is closer to the Equator than the United States