License, verbatimPD
The National Gallery of Art: open access image with no usage restrictions under the NGA's open access policy (openaccess=1 in the Gallery's published_images dataset).
Giuseppe Vasi after Giuseppe Palazzi (designer) and Paolo Posi (architect). The Prima Macchina for the Chinea of 1773: The Temple of Peace, 1773. National Gallery of Art, Washington.