How did people from america, europe, and africa come together? and what sort of nation did they build?

The American continent remained unknown to the rest of the world until Christopher Columbus discovered in 1492. From then on the Europeans started settling in colonies. Most of the European came to start a new life after wars in America, away from its own country. There were also Natives of America, who inhabitants America before its discovery. From Africa, the slaves were brought for colonies to survive in America, they worked in the fields, and did domestic work, which helped the settlers in investing in trade and flourishing the colonies.

The people from America, Europe, and Africa together built a nation, that today we know as the United States of America.

b) race riots in several cities

after the roman empire, the catholic church began to unify by taking on many duties of a government.