Streamline Moderne is an international style of Art Deco architecture and design that emerged in the 1930s. It was inspired by aerodynamic design. Streamline architecture emphasized curving forms, long horizontal lines, and sometimes nautical elements. In industrial design, it was used in railroad locomotives, telephones, toasters, buses, appliances, and other devices to give the impression of sleekness and modernity.
In France, it was called the Style Paquebot, or "Ocean liner style", and was influenced by the design of the luxury ocean liner SS Normandie, launched in 1932.
As the Great Depression of the 1930s progressed, Americans saw a new aspect of Art Deco, i.e., streamlining, a concept first conceived by industrial designers who stripped Art Deco design of its ornament in favor of the aerodynamic pure-line concept of motion and speed developed from scientific thinking. The cylindrical forms and long horizontal windowing in architecture may also have been influenced by constructivism, and by the New Objectivity artists, a movement connected to the German Werkbund. Examples of this style include the 1923 Mossehaus, the reconstruction of the corner of a Berlin office building in 1923 by Erich Mendelsohn and Richard Neutra. The Streamline Moderne was sometimes a reflection of austere economic times; Sharp angles were replaced with simple, aerodynamic curves. and ornament was replaced with smooth concrete and glass.
The style was the first to incorporate electric light into architectural structure. In the first-class dining room of the SS Normandie, fitted out 1933–35, twelve tall pillars of Lalique glass, and 38 columns lit from within illuminated the room. The Strand Palace Hotel foyer (1930), preserved from demolition by the Victoria and Albert Museum during 1969, was one of the first uses of internally lit architectural glass, and coincidentally was the first Moderne interior preserved in a museum.
Streamline moderne appeared most often in buildings related to transportation and movement, such as bus and train stations, airport terminals, roadside cafes, and port buildings. It had characteristics common with modern architecture, including a horizontal orientation, rounded corners, the use of glass brick walls or porthole windows, flat roofs, chrome-plated hardware, and horizontal grooves or lines in the walls. They were frequently white or in subdued pastel colors.
An example of this style is the Aquatic Park Bathhouse in the Aquatic Park Historic District, in San Francisco. Built beginning in 1936 by the Works Progress Administration, it features the distinctive horizontal lines, classic rounded corners railing and windows of the style, resembling the elements of ship. The interior preserves much of the original decoration and detail, including murals by artist and color theoretician Hilaire Hiler. The architects were William Mooser Jr. and William Mooser III. It is now the administrative center of Aquatic Park Historic District.
The Normandie Hotel in San Juan, Puerto Rico, which opened during 1942, is built in the stylized shape of the ocean liner SS Normandie, and displays the ship's original sign. The Sterling Streamliner Diners in New England were diners designed like streamlined trains.
Although Streamline Moderne houses are less common than streamline commercial buildings, residences do exist. The Lydecker House in Los Angeles, built by Howard Lydecker, is an example of Streamline Moderne design in residential architecture. In tract development, elements of the style were sometimes used as a variation in postwar row housing in San Francisco's Sunset District.
Aquatic Park Bathhouse, now part of the Aquatic Park Historic District San Francisco (1936)
Coca-Cola factory, Los Angeles by Robert V. Derrah (1936)
Former National Institute of Radio Broadcasting, Ixelles, Belgium (1938)
Pan-Pacific Auditorium in Los Angeles, California (1935-1989)
Hotel Shangri-La (1939), Santa Monica, California
In France, the style was called Pacquebot, or ocean liner. The French version was inspired by the launch of the ocean liner Normandie in 1935, which featured an Art Deco dining room with columns of Lalique crystal. Buildings using variants of the style appeared in Belgium and in Paris, notably in a building at 3 boulevard Victor in the 15th arrondissement, by the architect Pierre Patout. He was one of the founders of the Art Deco style. He designed the entrance to the Pavilion of a Collector at the 1925 Exposition of Decorative Arts, the birthplace of the style. He was also the designer of the interiors of three ocean liners, the Ile-de-France (1926), the l'Atlantique (1930), and the Normandie (1935).
Patout's building on Avenue Victor lacked the curving lines of the American version of the style, but it had a narrow "bow" at one end, where the site was narrow, long balconies like the decks of a ship, and a row of projections like smokestacks on the roof. Another 1935 Paris apartment building at 1 Avenue Paul-Daumier in the 16 arrondissement had a series of terraces modeled after the decks of an ocean liner. 
Main dining room of the ocean liner S.S. Normandie by Pierre Patout (1935)
The defining event for streamline moderne design in the United States was the 1933-34 Chicago World's Fair, which introduced the style to the general public. The new automobiles adapted the smooth lines of ocean liners and airships, giving the impression of efficiency, dynamism, and speed. The grills and windshields tilted backwards, cars sat lower and wider, and they featured smooth curves and horizontal speed lines. Examples include the 1934 Chrysler Airflow and the 1934 Studebaker Land Cruiser. The cars also featured new materials, including bakelite plastic, formica, Vitrolight opaque glass, stainless steel, and enamel, which gave the appearance of newness and sleekness. 
In 1939 and 1941 respectively, both Chrysler and GM came out with pick-up and truck lines, that had both distinct and similar looking designs that submitted to the Art Deco and streamline styling en vogue in the day, under various brand names.
Other later examples include the 1950 Nash Ambassador "Airflyte" sedan with its distinctive low fender lines, as well as Hudson's postwar cars, such as the Commodore, that "were distinctive streamliners—ponderous, massive automobiles with a style all their own".
The 1934 Tatra 77 was the first serial-produced truly aerodynamically designed automobile.
1934 Chrysler Airflow
Studebaker Land Cruiser (1934)
Bugatti Aérolithe (1936)
1937 Cord Automobile
1939 Schlörwagen - Subsequent wind tunnel tests yielded a drag coefficient of 0.113
1939 Dodge 'Job Rated' streamline model truck
1946 Chevrolet DP ½-ton 'Art Deco' pickup
Streamlining became a widespread design practice for aircraft, railroad locomotives, and ships.
Streamline style can be contrasted with functionalism, which was a leading design style in Europe at the same time. One reason for the simple designs in functionalism was to lower the production costs of the items, making them affordable to the large European working class. Streamlining and functionalism represent two different schools in modernistic industrial design.
The first bakelite telephone (1931)
Electrolux Vacuum cleaner (1937)
Streamlined Bakelite radio (1952)
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