The world's wealthiest country United States of America (USA) is the fourth and the third most populated country in the world. The USA is made up of 50 states, 48 of which occupy the central part of North America. Alaska, the 49th state lies in the north west of North America and Hawaii, the 50th state, is the chain of pacific islands. The USA is a major industrial and economic force, since 1945, it has also played a leading role in world affairs. A vast flat plain lies between the high Rockery mountains in the west and the weathered Appalachians of eastern USA. The Mississippi River flows south across the plain. Thick forests grown in the North West. One of the first regions to be settled by Euro cans immigrants the northeastern states have a rich historical and cultural heritage and are a melting pot of peoples and cultures. Rich mineral resources, and many good harbors and rivers, this area has become the most industrialized and heavily populated part of the USA. Busy cities such as Boston, New York, City, Pittsburgh, and Philadelphia, contrast with the unspoiled rural farmsteads of New England. More than 50 million people visit the USA every year and many come to the northeastern states. New York City covering an area of 780 sq km (30 / sq miles). New York City is the largest city in the USA and a leader in the arts, business, and finance. Wall Street's stock exchange is the worlds biggest. The news print media is facing increasing competition from satellite and cable television and the internet.