Cecil B. DeMille’s 1959 autobiography contains an odd passage: “If a thousand years from now, archaeologists happen to dig beneath the sands of Guadalupe, I hope they will not rush into print with the amazing news that Egyptian civilization, far from being confined to the valley of the Nile, extended all the way to the Pacific coast of North America. The sphinxes they will find were buried when we had finished with them and dismantled our huge set of the gates of Pharaoh’s city.”

He was referring to his 1923 silent film The Ten Commandments — after shooting was finished, he’d had the massive sets buried where they’d been built, in California’s Guadalupe-Nipomo Dunes. It’s not clear why — possibly he lacked the funds to remove them and didn’t want other filmmakers to use them. The sets included four Pharaoh statues 35 feet tall, 21 sphinxes, and gates 110 feet high, forming an ersatz Egyptian civilization for modern archaeologists to uncover.

Their time is limited. “It was like working with a hollow chocolate rabbit,” Doug Jenzen, executive director of the Guadalupe-Nipomo Dunes Center, told the Los Angeles Times of one dig in 2014. “These were built to last two months during filming in 1923, and these statues have been sitting out in the elements since then.”