Verona, the city of Romeo and Juliet, is mysteriously home to a centuries-old whalebone. The trouble is, Verona is located about 75 miles (120 km) from the sea, and no one is quite sure how it got there.

The bone, believed to be a rib, hangs in the center of the medieval Arco della Costa (Arch of the Rib), the entry point between Verona’s Piazza Erbe and Piazza dei Signori. It’s been hanging there, suspended from an iron chain, since at least the 1700s, though some estimates suggest much longer, possibly since the 15th century.

In the Middle Ages and Renaissance era, the walkway above the arch provided a safe passage for judges and magistrates between the city hall and their living quarters, so that they needn’t associate with the common or “corrupt” people below. This may be the ironic origin of the myth of the whalebone’s magic: It’s claimed that it will fall on the first innocent or truthful person to walk under the archway.