Allegorical figures representing navigation, enlightenment, and industry were created for the top of the building; the proportions of the figures were designed to be viewed from below. In 1966, the post office was demolished. The sculptures were placed here as part of the Pittsburgh History & Landmarks Foundation's Old Post Office Museum Artifact Garden, which was located on the site that is now the museum's parking lot. Many of the artifacts can still be found on the other side of the stone wall with plaques that describe their original location.
Eugenio Pedon was commissioned to create sculptures for federal buildings throughout the nation, including Pittsburgh's Fourth Avenue Post Office in 1880.