The fringe theories long attached to UNESCO sites

CNN  — 

Erich von Däniken dried his sweaty palms with granite dust as he scaled the Great Pyramid of Giza, crawling block by block up the nearly 4,000-year-old monument.

It was 1954, when you could still climb the pyramids. Von Däniken, a 19-year-old with a Catholic education and a passion for flying saucers, was captivated. Fourteen years later, he published an influential book called “Chariots of the Gods,” arguing that extraterrestrials influenced ancient sites, the pyramids included.

The magnificent Giza Pyramids are among the world’s most famous ancient places, part of a sprawling UNESCO World Heritage Site that brings travelers to Egypt from across the globe.

Visitors come to explore hidden burial chambers, go eye-to-eye with the mysterious Sphinx and take in the sheer scale of Egypt’s grandest monuments.

Von Däniken proposed that aliens offered technological help in building them.

The Giza Pyramids are among many ancient sites subject to alien theories.

What the scientists say about these famous places

Mainstream archaeologists disagree with Von Däniken, retorting that ancient Egyptians developed their remarkable building tradition with no help from extraterrestrials.

But while scientists are generally united in rejecting the aliens idea, sometimes known as “ancient astronaut theory,” Von Däniken’s ideas have endured.

He went on to write 32 additional volumes, selling more than 63 million copies. Penguin Random House, his publisher, claims Von Däniken is “arguably the most widely read and most-copied nonfiction author in the world.”

And the pyramids aren’t the only UNESCO site swept up in his theories, or in those of people he’s inspired.

Archaeologists see Teotihuacan in Mexico as the crowning achievement of a little-known -- but earthbound -- civilization.

Some speculate that the UNESCO site of Teotihuacan, where the Aztec kings once ruled near modern-day Mexico City, could have been a space port, pointing to mica and liquid mercury found among the ruins that they say are anachronistic.

For travelers, Teotihuacan is a glimpse into an ancient, mysterious empire. Researchers believe the city predates even the Aztecs, who were living there when Europeans first arrived in Mexico.

Archaeologists, who have carried out painstaking excavations here for centuries, see it as the crowning achievement of a little-known – but earthbound – civilization.

Instead of peering up toward space, they dig into the ground. Archaeologists have spent years excavating a tunnel at Teotihuacan, which leads to chambers full of ritual offerings that some believe symbolize the underworld.