>>508745790
>Doesn't know there was countless feet, inch, etc. standards
Ex : Iberian railroad gauge (1668 mm) is an half-way meet between Spanish (6 Spanish feet=1672 mm) and Portuguese (5 Portuguese feet=1664 mm) gauges.
>Spanish foot: 278.(6) mm
>Portuguese foot: 332.8 mm
>Imperial foot: 308.4 mm
Multiply by dozens of countries; imagine the nightmare...