In the United States, out-of-work artists who were employed under the Federal Art Project during the Great Depression era drew wall paintings on public buildings, and in communist countries, many wall paintings were created to deliver political slogans and for propaganda purposes.
その他アメリカ合衆国でも大恐慌の際に連邦美術計画によって失業画家を雇って公共建築に壁画が描かれ、共産主義国では多くの政治的スローガンと共にプロパガンダ用の壁画が描かれた。