The Geodata plugin allows you to add a data source that creates objects for countries, cities, and currencies which can be used in data streams that come from other data sources.
It's a utility plugin that can add data sources without entering any credentials, which means you don't have to create an API key, user account, or anything like that.
Tip: The OpenWeatherMap data source is a great addition to the Geodata data source. It enables you to see weather data for the cities and countries the Geodata data source created. See OpenWeatherMap plugin.