The pavilion’s round ground plan is rendered more elaborate by two rectangular projections. The entrance takes the form of a niche with a door placed at the back of it. The curving areas of the façade between the projections are embellished with columns.
When creating the Kitchen Ruin Quarenghi reused fragments of genuine ancient edifices that he had at his disposal – marble capitals, a cornice and a frieze with carved garlands. In the upper part of the walls and in the gaps between the columns he placed six plaster bas-reliefs that were cast by the sculptor Concesio Albani and deliberately damaged to give them the appearance of great antiquity that would inspire melancholy reflection.
Quarenghi placed genuine ancient sculptures in the niches on the façades and he also installed a few pieces (that have not survived) inside. The builders imitated a ruined edifice from the ancient world with exceptional skill: in places dilapidated brickwork has been laid bare; the cornice and the plaster on the walls are covered with cracks. In the words of Igor Grabar, Quarenghi constructed “a ruin of such enchanting, persuasive authenticity that it is hard to believe in its falseness.”