Just what makes Pittsburgh's sandwich so iconic?
In November, the BBC Pop Up team visited Pittsburgh, Pennsylvania. Almost everyone they talked to mentioned the Primanti Brothers' sandwich.
The chip-and-meat sandwiches that servers sling from the kitchen have come to symbolise the Steel City. But why is that?
As BBC Pop Up journalist Benjamin Zand finds out it's all in the arrangement of the ingredients.
Produced by Matt Danzico