The Central Intelligence Agency (CIA) of the United States maintains a free, useful, no-strings-attached (that we know about) database of information about the countries of the world. Despite the reputation of daring spywork, CIA also has the comparatively boring role of compiling useful information about places all over the world.

The agency makes some of this information available to anyone that can use a web browser. If anyone from the agency is reading this book (hopefully through a purchase and not directly from the author's laptop - but we kid, we kid), the author would like to thank you for making this great source of global information available for free. It is available as public domain, which means no worries about copyright or reserved publication rights issues.

The World Factbook includes information about over 260 world entities (as they term it, but think countries). The information is on things such as the history, people, government, economy, geography, communications, transportation, and military for each country.

However, the World Factbook is not available in machine-readable form from the website; you can find a JSON version on GitHub. It is a useful reference for understanding various countries of the world if your IoT devices are globally distributed. It is available at https://www.cia.gov/library/publications/the-world-factbook/.