List of United States post office murals
From 1934 to 1943, the Procurement Division of the United States Department of the Treasury commissioned murals in post office buildings across the country. Part of the New Deal, the stated objective of commissioning United States post office murals was to secure artwork that met high artistic standards for public buildings, where it would be accessible to all people.
Source: Wikipedia — List of United States post office murals (CC BY-SA 4.0)