License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
François Debret. Grotto from the Gardens of the Farnese Palace at Caprarola, Preparatory Study for the 'Oeuvres Complètes de Jacques Barozzi de Vignole', 1815–23. The Metropolitan Museum of Art.