Science historian Adrienne Mayor shared her research into how pre-scientific cultures understood the fossil record, and how their interpretation formed the basis of many ancient legends. According to Mayor, fossils were easily found in the ancient Greco-Roman world due to the region's seismic activity, as well as erosion caused by thunderstorms and landslides. Mayor said the simple act of plowing a field could reveal fossilized remains, which would then be collected, measured, and put on display at a local Temple. Isolated bones from mastodons or giant rhinoceroses were often misidentified as monsters or heroes from myth, Mayor explained.

Native Americans had their own stories about creatures of legend. Mayor thinks Paleo-Indians may have encountered giants in certain areas of America. They likely lived alongside very large birds as well. As evidence, Mayor noted that a huge bird with a 15-ft wingspan, known as a Teratorn, co-existed with early humans in Africa. She also pointed to a petroglyph at Petrified Forest National Monument in Arizona that depicts a giant bird with a person in its beak.

Mayor spoke about Fifth century Greek historian Herodotus, who claimed to have been shown evidence of flying snakes in Egypt. Roman statesman Cicero also mentioned winged reptiles, she explained, as did a Medicine Man from the Crow Tribe, who told his granddaughter that he had found a flying lizard during a vision quest.

Mayor discussed giant sea creatures mentioned in the Bible and elsewhere in ancient literature (Pliny the Elder), as well as presented stories about UFOs in antiquity. In one such tale, natives in Ecuador and Peru showed Spanish explorers bones belonging to what they described as giant invaders from the sea. Mayor said the natives informed the explorers about a flash of fire from the heavens that destroyed the huge creatures and left only their charred remains behind. In an account from 74 BC, two warring armies witnessed a flaming object crash into their battlefield. The object was described as molten silver in color and shaped like a nose cone, Mayor said.