The Empire State Building is one of the most iconic real estate landmarks in the world. But even though millions of people visit it every year, we've only recently been given the opportunity to see its financial performance as its owner, the Empire State Realty Trust (NYSE:ESRT), became a publicly traded company in 2013.

Because Empire State Realty Trust is obligated to file quarterly and annual financial reports with the Securities and Exchange Commission, investors and other interested people can now discover not only how much money the Empire State Building earns, but also exactly how the skyscraper makes its money.

You'd be excused for thinking that the answer to the latter question is obvious; it is, after all, one of the largest office buildings in the world. But while Empire State Realty Trust does indeed generate a considerable amount of revenue from office leases, this is actually the second largest source of revenue from its marquee real estate asset. To learn how the Empire State Building earns even more money, I encourage you to scroll through the brief slideshow below.

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