The Empire State Building was completed in 1931, at the height of the Great Depression. Because of the state of the economy at that time, approximately 77% of its office space remained unleased for years, which made New Yorkers start calling it “The Empty Space Building”, a play on its name.

These days, space in the Empire State Building is not only scarce, but also some of the most expensive real estate in Manhattan.

Source: https://ballenvegas.com/101-real-estate-facts/