Everyone thinks about lost luggage. Less about the simple yet effective design of the luggage tag.

A Pan Am tag and a modern one (more photographs in the original Slate article)

In the interconnected, automated, all-weather world of modern aviation, tags must be resistant to cold, heat, sunlight, ice, oil, and especially moisture. Tags also can’t tear—and crucially, if they’re nicked, they must not tear further—as the bag lurches through mechanized airport baggage systems. And the tag must be flexible, inexpensive, and disposable.

Bag tags must meet another set of contradictory requirements. They must be easy to attach, but impossible to detach.

Yeah, all that.