Labor needed to operate the bustling port, a booming manufacturing industry and the defense industries that located here during World War I created an ever-increasing demand for housing. Residential neighborhoods began to spread out over both the flatlands formerly used for agriculture and the East Bay's hillsides, creating the prototype of the sprawling California city. Montclair, shown here when its first home sites went on sale in the 1920s, would develop its own unique character, as many of the city's districts have.