A shipbuilding boom in the early part of the 20th century became massive during World War I, making Seattle somewhat of a company town; the subsequent retrenchment led to the Seattle General Strike of 1919, the first general strike in the country. A 1912 city development plan by Virgil Bogue went largely unused. Seattle was mildly prosperous in the 1920s but was particularly hard hit in the Great Depression, experiencing some of the country's harshest labor strife in that era. Violence during the Maritime Strike of 1934 cost Seattle much of its maritime traffic, which was rerouted to the Port of Los Angeles.

When was ship building the economic master in Seattle?