License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Giovanni Battista Piranesi. Remains of ancient buldings among which stands the sepulchral urn of Marcus Agrippa made entirely of porphyry, which serves today as the Tomb of Clement XII... (Vestiggi d'antichi Edifici fra i quali evvi l'Urna Sepolcrale tutta d'un pezzo di...), from "Prima Parte di Architettura, e Prospettive", ca. 1750. The Metropolitan Museum of Art.