Short answers, pulled from the story.
The United States Constitution took effect on the 4th of March 1789. This date marks the beginning of a system where sovereign power is formally divided between a central authority and constituent regions.
Six federations exist in Africa today. There are currently 27 federations in existence across all continents with six located specifically on that continent.
The Federal Republic of Central America broke up into independent states less than 20 years after its founding. Some New World federations failed quickly including this specific example which dissolved within two decades.
India, Pakistan, Nigeria and Malaysia became federations on or shortly before becoming independent from the British Empire. These nations transitioned to federal systems during their decolonization process.
Nepal established seven provinces following its constitution taking effect on the 20th of September 2015. The new structure covers vast geographic areas while managing different ethnic groups.