Standard list of countries, cities, states

https://www.unece.org/cefact/locode/service/location.html

https://help.salesforce.com/articleView?id=000230216&type=1

https://www.iso.org/iso-3166-country-codes.html



https://en.wikipedia.org/wiki/IATA_airport_code
https://stackoverflow.com/questions/7066825/is-there-an-iso-standard-for-city-identification