country_codes.json:
https://github.com/venkatmcajj/react-country-state-city/blob/master/data/countriesminified.json

regions.json:
https://github.com/venkatmcajj/react-country-state-city/blob/master/data/statesminified.json

cities500_updates.json:
https://download.geonames.org/export/dump/