The Ancient Astronaut Hypothesis
The book followed two earlier French bestsellers that had already laid the groundwork, and its own author was later convicted of fraud unrelated to its claims. The sites it names as too advanced for their builders are almost never in Europe — a pattern its critics treat as the real subject.
Erich von Däniken, Chariots of the Gods? (1968), following Pauwels and Bergier's Le Matin des Magiciens (1960)
The claim that extraterrestrials built ancient monuments like Giza, Nazca and Puma Punku, popularised by a 1968 bestseller.