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 Pozzi, after Giuseppe Palazzi, after Paolo Posi. The Prima Macchina for the Chinea of 1757: The Colonnade of the Athenian Lyceum, 1757. National Gallery of Art, Washington.