it even made recommendations on the ideal number of bedrooms and other rooms per house. Although the semi-detached house was first designed by the Shaws (a father and son architectural partnership) in the 19th century, it was during the suburban housing boom of the interwar period that the design first proliferated as a suburban icon, being preferred by middle-class home owners to the smaller terraced houses. The design of many of these houses, highly characteristic of the era, was heavily influenced by the Art Deco movement, taking influence from Tudor Revival, chalet style, and even ship design. Within just a decade suburbs dramatically increased in size. Harrow Weald went from just 1,500 to over 10,000 while Pinner jumped from 3,000 to over 20,000. During the 1930s, over 4 million new suburban houses were built, the 'suburban revolution' had made England the most heavily suburbanized country in the world, by a considerable margin. North America Boston and New York City spawned the first major suburbs. The streetcar lines in Boston and the rail lines in Manhattan made daily commutes possible. No metropolitan area in the world was as well served by railroad commuter lines at the turn of the twentieth century as New York, and it was the rail lines to Westchester from the Grand Central Terminal commuter hub that enabled its development. Westchester's true importance in the history of American suburbanization derives from the upper-middle class development of villages including Scarsdale, New Rochelle and Rye serving thousands of businessmen and executives from Manhattan. Postwar suburban expansion The suburban population in North America exploded during the post-World War II economic expansion. Returning veterans wishing to start a settled life moved in masses to the suburbs. Levittown developed as a major prototype of mass-produced housing. Due to the influx of people in these suburban areas, the amount of shopping centers began to increase as suburban America took shape. These malls helped supply goods and services to the growing urban population. Shopping for different goods and services in one central location without having to travel to multiple locations, helped to keep shopping centers a component of these newly designed suburbs which were booming in population. The television helped contribute to the rise of shopping centers due to the increased advertisement on television in addition to a desire to have products shown in suburban life in various television programs. Another factor that led to