Raised the standard of living for higher classes, but made it more difficult for the lower classes. In the 1860's, 1/5 textile workers were under 15 years old. Overcrowded, unsanitary living conditions with disease. By the mid-19th century, industrialization was well-established throughout the western part of Europe and America’s northeastern region. By the early 20th century, the U.S. had become the world’s leading industrial nation.