How to create a tree view of several countries with cities?

Question

PHP

How do they create such lists as Yandex Wordstat, for example, so that there is Russia and Ukraine with Belarus?
It is unlikely that all cities are entered manually.

Answer 1

Well, you can download and save once to a file or to a database in the structure you need, or use api every time, for example, you can use the VKontakte database https://vk.com/dev/database