The Singer Building or Singer Tower, a 47-story office building for the Singer Sewing Machine Company located at Liberty Street and Broadway in Manhattan, was the tallest building in the world when completed. It was demolished in 1968.
 
The observation balcony was on the fortieth floor. The New York (NY) Herald Tribune stated on November 14, 1939:
 
“Thousands of sightseers paid 50 cents to ride to the observation balcony of the tower until, after two suicide leaps, it became known as “Suicide Pinnacle,” and finally was closed to the public.”
       
   
Wikipedia: Singer Building
The Singer Building or Singer Tower, at Liberty Street and Broadway in Lower Manhattan’s Financial District, in the U.S. state of New York, was a 47-story office building completed in 1908 as the headquarters of the Singer Manufacturing Company. It was the tallest building in the world from 1908 to 1909. It was torn down in 1968, together with the adjacent City Investing Building, and is now the site of One Liberty Plaza. When it was razed, it became the tallest building ever to be demolished, and is currently the third-tallest building ever to be destroyed (after the World Trade Center towers) and the tallest to be purposely demolished by its owner.
   
14 November 1939, New York (NY) Herald Tribune, “New Copper Trimmings Fitted On Dome Of Singer Building, pg. 20, cols. 1-2:
Now thirty-one years old, the building, which is the home of the Singer Sewing Machine Company, no longer claims the title, “Pride of America,” as it did in 1908, when the forty-one-story structure was completed. At that time it was the world’s tallest office building, towering 612 feet above Broadway. The firs of the super-skyscrapers and the first building in New York to incorporate the setback feature, it was a part of New York which no visitor missed. Thousands of sightseers paid 50 cents to ride to the observation balcony of the tower until, after two suicide leaps, it became known as “Suicide Pinnacle,” and finally was closed to the public.
 
Google Books
New York City Skyscrapers
By Richard Panchyk
Charleston, SC: Arcadia Publishing
2010
Pg. 43:
SINGER BUILDING. (...) The observation balcony was soon given the nickname “Suicide Pinnacle” because of some people’s proclivity to jump upon reaching the top. It was the tallest building in the world until the completion of the Metropolitan Life Building a year later.
 
Google Books
Greater Gotham:
A History of New York City from 1898 to 1919
By Mike Wallace
New York, NY: Oxford University Press
2017
Pg. ?:
Thousands paid fifty cents for a ride to the “observation balcony” on the fortieth floor. Some took a shortcut down: the viewpoint attracted death trippers rather than ankle fetishists and soon became known as Suicide Pinnacle.