Caught tail end of "native america" on PBS last night.
http://www.pbs.org/native-america/home/
New documentary for me. They were showing evidence of native americans in inland Brazil ---via Amazon river-- some 25,000 years ago. These primitive peoples made wall paintings on the tall outside rock surface that faced west.
On far south face there is what this dude figured out was setting sun at winter solstice setting on some hourglass shaped shelf. He went at solstice to see if the shelf was actually a rock cropping a few miles away in sight to see if the sun set on that rock shelf.
It did and confirmed his speculations. There is also recordings of sun and the at opposite end{ north face } of the rock wall with sun setting on longest day of the year.
So these people may or nay not have concived of celestial objects orbiting our spherical planet. The program presumed they were sea-poeples who used canoes to travel from land mass north of Alaska.
This all falls along with Bucky Fullers ideas presented in his book Critical Path.