New York is the most populous city in the United States, and serves as the core of New York Metropolitan Area, the largest metropolitan area in the world. For over a century, New York has exerted a heavy global influence in commerce and finance, and has also been rated as a world-class city. New York directly affects the global media, politics, education, entertainment and fashion. The headquarters of the United Nations is also located in this city. In early 20th century, New York was a new world full of opportunities for immigrants, so New York is often nicknamed as "the Big Apple", which means "good-looking, delicious, and everyone wants to take a bite".