John Quincy Adams, the sixth President of the United States, was a top student at Harvard, one of America’s greatest diplomats, and successfully defended mutineers aboard the slave ship La Amistad as freemen in 1841. He also believed that the Earth was hollow and filled with other, potentially inhabited subterranean worlds.

During his presidency (1825-29), he said yes to funding a real-life journey to the center of the Earth to uncover what lies beneath our planet’s outer shell and find the mole people that dwell there. Adams may have been a believer in the hollow Earth theory, the idea that the Earth is completely hollow, containing more hollow shells, each with their own atmospheres. Think Russian dolls on a planetary scale. 

Whether he truly believed little men might be minding their own business below the Earth’s crust is anyone’s guess, but Adams was a huge fan of the natural world and exploration. The idea of a hollow Earth has been around for centuries, with underworlds and subterranean hells popping up across religions and cultures throughout history. But it wasn’t until the 19th century that proponents of the hollow Earth theory believed it might be possible to access our planet’s inner layers via vast holes in Earth's crust.

John Cleves Symmes Jr., an American army officer and lecturer, popularized his own spin on the hollow Earth theory in the 1820s. He thought that there were huge openings at the Earth’s poles that allowed access to the planet’s inner shells. And who can blame him? Back then, no one had a clue what lurked at the poles. After all, the first expedition to make it to the south pole was led by Roald Amundsen in 1911, and the first flight over the north pole wasn’t until 1926.

To prove his theory, Symmes decided to lead an expedition to the north pole hole to climb inside and come face to face with Earth’s subterranean beings. He published a circular proclaiming his belief and imploring 100 “brave companions” to join him on his mission, which would set off from Siberia across “the ice of the frozen sea” with the help of some trusty reindeer.

“I engage we find warm and rich land, stocked with thrifty vegetables and animals if not men, on reaching one degree northward of latitude 82,” Symmes wrote in the circular, which can be read in full on Slate.

But how do you fund such an expedition? With a little help from the government, of course. That’s where Adams comes in, who, despite much ridicule of the hollow Earth theory at the time, may have believed what Symmes was preaching, and gave the mission to the north pole and below the green light. 

However, in 1829 Adams was voted out of office and succeeded by a new president, Andrew Jackson. Under his leadership, the expedition was scrapped, and Symmes never got to meet the mole people hiding beneath the Earth’s crust. Unfortunately for Symmes, the explorers that would finally make it to the poles following his death in 1829 failed to discover the vast entrances to Earth's mysterious underworlds that he had so longed to find.