What are the great changes that have not happened in a hundred years?

Major changes that have not happened in the past century include: changes in the center of gravity of the world economy, changes in the world political structure, changes in the process of globalization, changes in science and technology and industry, and changes in global governance. Great changes have taken place in the past century, and the center of gravity of the world economy has changed: it is said that the United States became the world's largest creditor and capital exporter after World War I, and the center of gravity of the world economy shifted from the east coast of the Atlantic (Western Europe) to the west coast of the Atlantic (the United States), which is a great change in economic geography. At present, the transfer from the Atlantic to the Pacific has far exceeded the last time. The United States, the full name of the United States of America, is a federal constitutional country, which consists of Washington, D.C., 50 states, Guam and many other overseas territories. Its main part is located in central North America, and its territory also includes Alaska in northwest North America and Hawaii Islands in the central Pacific Ocean. It borders Canada in the north, the Gulf of Mexico in the south, the Pacific Ocean in the west and the Atlantic Ocean in the east. The United States was the first place where Indians lived. At the end of 15, Spain, the Netherlands, France and Britain immigrated here one after another. 13 Before the 8th century, Britain established13 British North American colony on the Atlantic coast of the United States.