In 1940, New York was already a world trade center, culture and industry. At that time, New York had a population of about 7,5 million, making it the largest city in the United States. The Great Depression of the 1930s was over and the city was beginning to grow and prosper again, mainly thanks to government programs and industrial development, which was strengthened after the Second World War. The financial sector on Wall Street was already dominant at the time and New York was the center of banking and investment, a fact that ensured her a strong financial position.

During World War II, the city became an important center of military production. Many factories in and around New York were converted to produce military equipment, which brought job opportunities and stimulated the economy. Infrastructure development was supported by government programs such as the New Deal, which allowed the construction of public buildings, roads and bridges.

The communities were very diverse – New York was home to many immigrants from Europe, but also African Americans who came here from the south of the country for better living conditions and work opportunities. Cultural and ethnic neighborhoods were created here, like Little Italy, Chinatown and Harlem, which gave the city a multicultural character.

1940 also saw the beginning of the golden age of Broadway musicals and the city became the cultural center of the US, with a booming music, film and literary scene. At that time, Harlem was the birthplace of African American culture, especially jazz music, which became one of the US's most important cultural exports. New York was driven by trade, the industry, economics and culture, which together created the energy and character that made New York 'the city that never sleeps'.