Why shouldn't it be on/. ?
This is a 'nerdy' item, and a rather sad one as well. Rather this than the endless, tedious and (to me and many others) redundant posts relating to US politics.
Looking at the number of posters whose place of birth no longer exists, are we to believe that dotted around the surface of the Earth are various black holes or null-fields or other phenomena where the normality of the familiar space-time continuum has simply........vanished?!