What year was the Brooklyn Bridge designated as a National Historic Landmark?

The Brooklyn Bridge is a hybrid cable-stayed/suspension bridge in New York City and is one of the oldest bridges of either type in the United States. Completed in 1883, it connects the boroughs of Manhattan and Brooklyn by spanning the East River. It has a main span of 1,595.5 feet (486.3 m) and was the first steel-wire suspension bridge constructed. It was originally referred to as the New York and Brooklyn Bridge and as the East River Bridge, but it was later dubbed the Brooklyn Bridge, a name coming from an earlier January 25, 1867, letter to the editor of the "The Brooklyn Daily Eagle" and formally so named by the city government in 1915. Since opening, it has become an icon of New York City and was designated a National Historic Landmark in 1964 and a National Historic Civil Engineering Landmark in 1972.

The bridge—originally referred to as the New York and Brooklyn Bridge and as the East River Bridge— was opened for use on May 24, 1883. On that first day, a total of 1,800 vehicles and 150,300 people crossed what was then the only land passage between Manhattan and Brooklyn. Emily Warren Roebling was the first to cross the bridge. The bridge's main span over the East River is 1,595 feet 6 inches (486.3 m). The bridge cost US$15.5 million in 1883 dollars (about US$385,554,000 in today's dollars) to build and an estimated 27 people died during its construction.