“The world is moved along, not only by the mighty shoves of its heroes,” social activist Helen Keller wrote in 1908, “but also by the aggregate of the tiny pushes of each honest worker.” The Made in America: Building a Nation stamps honor the courageous workers who helped build our country.

The sheet features 12 stamps in three rows of four. Eleven of the 12 stamp images were taken by photographer Lewis Hine, a chronicler of early 20th-century industry.

In the top row are an airplane maker, a derrick man on the Empire State Building, a millinery apprentice, and a man on a hoisting ball on the Empire State Building. In the middle row are a linotyper in a publishing house, a welder on the Empire State Building, a coal miner, and riveters on the Empire State Building. (The coal miner stamp is the only one of the 12 that does not feature a Hine photograph. The image is from the Kansas Historical Society.) In the bottom row are a powerhouse mechanic, a railroad track walker, a textile worker, and a man guiding a beam on the Empire State Building.