To work upon the world of created things and to magnify darkness or light, as we choose, to glorify good or evil, as we choose, to exalt love or hate… - Graham Hancock

The Julian calendar, which it replaced, computed the period of the earth's orbit around the sun at 365.25 days. Pope Gregory XIII's reform substituted a finer and more accurate calculation: 365.2425 days. Thanks to scientific advances since 1582 we now know that the exact length of the solar year is 365.2422 days.

Quetzalcoatl, the Feathered Serpent, [...] came to teach [the ancient inhabitants of Mexico] the benefits of settled agriculture and the skills necessary to build temples. Although this deity is frequently depicted as a serpent, he is more often shown in human form — the serpent being his symbol and his alter ego — and is usually described as "a tall bearded white man" ... "a mysterious person ... a white man with a strong formation of body, broad forehead, large eyes and a flowing beard." Indeed, [...] the attributes and life history of Quetzalcoatl are so human that it is not improbable that he may have been an actual historical character ... the memory of whose benefactions lingered after his death, and whose personality was eventually deified. The same could very well be said of Oannes — and just like Oannes at the head of the Apkallu (likewise depicted as prominently bearded) it seems that Quetzalcoatl traveled with his own brotherhood of sages and magicians. We learn that they arrived in Mexico "from across the sea in a boat that moved by itself without paddles," and that Quetzalcoatl was regarded as having been "the founder of cities, the framer of laws and the teacher of the calendar."

The Piri Reis map of 1513 features the western shores of Africa and the eastern shores of North and South America and is also controversially claimed to depict Ice Age Antarctica — as an extension of the southern tip of South America.
The same map depicts a large island lying east of the southeast coast of what is now the United States. Also clearly depicted running along the spine of this island is a 'road' of huge megaliths. In this exact spot during the lowered sea levels of the Ice Age a large island was indeed located until approximately 12,400 years ago. A remnant survives today in the form of the islands of Andros and Bimini. Underwater off Bimini I have scuba-dived on a road of great megaliths exactly like those depicted above water on the Piri Reis map.
Again, the implication, regardless of the separate controversy of whether the so-called Bimini Road is a man-made or natural feature, is that the region must have been explored and mapped before the great floods at the end of the Ice Age caused the sea level to rise and submerged the megaliths.