There is no clear beginning or singular building that can be marked as the start of modernism in architecture.European architects such as Adolph Loos, Otto Wagner, Le Corbusier, Mies van der Rohe, Eric Mendelson, and Walter Gropius were early proponents of modern philosophies.American architects such as Louis Sullivan, Philip Johnson, Frank Lloyd Wright, Albert Frey, Irving Gill, Rudolph Schindler, and Richard Neutra worked in the modern idiom throughout the United States.Slowly their work and ideas would infiltrate society, and modernism began to take a strong foothold in architectural circles The Industrial Revolution also played a significant role in the development of modern architecture.Skyscrapers, train stations, airports, factories, and office buildings became ubiquitous in major cities worldwide.Sanitation and health entered the architectural discourse.