The mid-20th century saw substantial growth in Rockville, especially with the annexation of the Twinbrook subdivision in 1949, which added hundreds of new homes and thousands of new residents to the city. In 1954, Congressional Airport closed, and its land was sold to developers to build residences and a commercial shopping center. The shopping center, named Congressional Plaza, opened in 1958. These new areas provided affordable housing and grew quickly with young families eager to start their lives following World War II.