The New York skyline is very much dominated by skyscrapers, such as the Empire State Building, the Chrysler Building, and the One World Trade Center. There are many metaphors that come to mind when looking at the skyline of New York, but the one that I would suggest is to compare the New York skyline to swords.
Swords are long and sharp weapons that reach up when held upright, just like the skyscrapers of New York. Also, just like the skyscrapers, swords gleam and glisten in the sunlight, reflecting the light from the sun in different angles. Swords are symbols of power, and so are many of the buildings that define the New York skyline: the Empire State building hosts many very successful companies, such as LinkedIn, for example. The Trump Tower hosts the headquarters of the powerful Trump Organization.
Therefore, you could say that just like swords represent strength and power, the buildings of New York represent the strength of the American economy. Through the business deals being made in many of these buildings, the American economy is able to keep growing, bringing strength and power to the country. Also, just like swords, the economic power houses contained in these buildings help the country to stay safe and to protect it from danger. They protect the country's economy just like a sword offers protection.