No one knows how it started. No one knows who was responsible. Some may even have dismissed it as an aberration, a glitch in the scenery that would soon be corrected. But eventually, drivers in and around Des Peres, Missouri who took a highway off-ramp connecting I-270 North to Manchester Road began to notice that a jar of pickles was sitting on a dividing barrier on the ramp. And it wasn’t going anywhere.

Since 2012, the pickle jar has confounded drivers and internet sleuths alike, according to Atlas Obscura. Some have speculated that someone was trying to send a secret message or share a private joke. Perhaps someone pulling off to the side due to car trouble felt the need to place the brine-filled jar on the concrete wall and then forgot about it. Maybe someone thought it would be a kind of three-dimensional graffiti, incongruous amid the bustling traffic. Maybe it’s an indictment of commerce.

Whatever the case, once the pickles appeared, advocates refused to let them go. Jars that end up toppled over or otherwise damaged are replaced. Sometimes they reappear in protective plastic containers or with a holiday-themed bow. Sightings are photographed for posterity and posted on a Facebook fan page devoted to the jar, which currently has over 4200 members and has morphed from a place to theorize about the mysterious jar's origins to a place where people swap pickle-related recipes and stories.

There are dry spells—no one has posted of a pickle sighting in several months—but followers remain optimistic the jar will continue to remain a presence in Des Peres even if the motivation for placing them near the roadway remains as murky as the briny juice inside.

[h/t Atlas Obscura]