Final answer:
The idea that intelligent aliens were responsible for ancient technological achievements like the Mayan calendar and Stonehenge is false, as history and archaeology have proven these were human accomplishments.
Step-by-step explanation:
The statement suggesting that the Mayan calendar, Sumerian references to gods, and Stonehenge are proof of ancient alien visitors is false. Archaeological and historical evidence clearly indicates that these achievements were made by ancient humans, who possessed great ingenuity and were capable of technological advances even without modern tools. Civilizations such as the Mesopotamians were remarkable engineers, mathematicians, and astronomers. They developed systems of mathematics, agriculture, and timekeeping that greatly contributed to what we understand as modern civilization.
As an example, the ancient Sumerians not only created cuneiform writing but also made significant advances in astronomy, which allowed them to create star charts and calendars. The belief that ancient structures or knowledge could only come from extraterrestrial beings underestimates human potential and discredits the proven accomplishments of our ancestors.