New York City (officially the City of New York) is the largest city in the United States and one of the world's major global cities. Located in the state of New York, the city has a population of over 8.1 million within an area of 321 square miles (approximately 830 square km), making it the most densely populated major city in North America. Its metropolitan area has a population of 18.7 million and is one of the largest urban areas in the world. New York City is an international center for business, finance, fashion, medicine, entertainment, media, and culture, with an extraordinary collection of museums, galleries, performance venues, media outlets, international corporations, and financial markets. The city is also home to the headquarters of the United Nations, and to many of the world's most famous skyscrapers. Popularly known as the "Big Apple", the "City That Never Sleeps", or the "Capital of the World", the city attracts large numbers of immigrants, as well as people from all over the United States who come for its culture, diversity, fast-paced lifestyle, cosmopolitanism, and economic opportunity. The city is also currently distinguished for having the lowest crime rate among major American cities.