Beginning about 1500 AD, Europeans took advantage of new advances in sail technology to invade and take over most of the world beyond Europe. Their colonization had disastrous effects for the people they conquered.
The Europeans began by sailing down the Atlantic coast of Africa. They went around Africa to India. And soon they took control of India. The Europeans began to buy spices and silk directly from India and China, instead of going through the old Silk Road and the Islamic empire‘s traders. So the Ottoman Empire in Iraq, the Safavids in Iran, and Russia became much poorer than they had been before.
Soon the Europeans also invaded South America. They accidentally infected the Incas, Aztecs, and Maya with smallpox and measles and dysentery, malaria and yellow fever. Most of the people of North and South America died. So the Europeans were able to take over as rulers in both continents. To replace the people who had died, the Europeans bought people in Africa. They brought Africans over to North America and Brazil as slaves.
In the last 150 years, more big changes came to the world. First, the people invented motorized machines. Now most people didn’t have to work on farms. Most people could live in cities while only a few people worked on farms. Second, the native people of most of the conquered countries got back control of their countries. They are just beginning to rebuild their countries. But they have the disadvantage that the Europeans still have most of the money and are still writing most of the rules.