An airline route.
When the continents figure out a global currency.
When there exist no borders around countries.
When people are free to emigrate & work after upgrading to a standardized system of industry practice & training.

When you eat dirt for the first time and leave your family to build a shack in the woods

A sexual act performed by two male transvestites of differing nationalities when they stand back to back with a double-sided dildo inserted. Each can then masturbate simultaneously.