美国, or the United States of America, is a country located in North America. It is made up of 50 states, with 华盛顿特区 as its capital. The country is known for its diverse culture, economy, and geography, ranging from mountains to plains and coastlines. The United States has a significant influence on global politics, economics, and culture. It is home to many renowned institutions, including 哈佛大学 and 斯坦福大学, and is a leader in technology and innovation. The country also has a rich history, marked by events such as the 独立战争 and the 民权运动.