A set of photographs published on image sharing website Imgur last week show what the photographer referred to as a “human roller coaster” in North Korea.

While standing at the Taesongsan Revolutionary Martyrs’ Cemetery during a 2012 trip to North Korea, the photographer took photos of a nearby roller coaster. But after zooming in on the photos, the photographer writes, “something was definitely strange.”

Some media reports have republished the photographs and similarly speculated that this may be a “human roller coaster” describing lines of perhaps hundreds of humans on the tracks but providing little explanation.

The notion of a