The temple of Mars stands at the north-eastern corner of the magnificent _Forum of Augustus_, which extended from here as far as the present Via Alessandrina, surpassing in size the forum of Julius Cæsar, to which it was adjoining. It was of sufficient size to be frequently used for fights of animals (venationes). Among its ornaments were statues of Augustus triumphant and of the subdued provinces--with inscriptions illustrative of the great deeds he had accomplished there; also a picture by Apelles representing War with her hands bound behind her, seated upon a pile of arms. Part of the boundary wall exists, enclosing on two sides the remains of the temple of Mars Ultor, and is constructed of huge masses of peperino. The arch, in the wall close to the temple, is known as Arco dei Pantani. The sudden turn in the wall here is interesting as commemorating a concession made to the wish of some proprietors, who were unwilling to part with their houses for the sake of the forum. "C'est l'histoire du moulin de Sans-Souci, qui du reste paraît n'être pas vraie. "Il est piquant d'assister aujourd'hui à ce ménagement d'Auguste pour l'opinion qu'il voulait gagner. Envoyant le mur s'infléchir parce-qu'il a fallu épargner quelques maisons, on croit voir la toute-puissance d'Auguste gauchir à dessein devant les intérêts particuliers, seule puissance avec laquelle il reste à compter quand tout intérêt général a disparu. L'obliquité de la politique d'Auguste est visible dans l'obliquité de ce mur, qui montre et rend pour ainsi dire palpable le manège adroit de la tyrannie, se déguisant pour se fonder. Le mur biaise, comme biaisa constamment l'empereur."--_Ampère, Emp._ i. 233. (The street on the left--passing the Arco dei Pantani--the Via della Salita del Grillo, commemorates the approach to the castle of the great mediæval family Del Grillo; the street on the right leads through the ancient Suburra.) At the corner of the next street (Via della Croce Bianca)--on the left of the Via Alessandrina--is the ruin called the "Colonnace," being part of the _Portico of Pallas Minerva_, which decorated the _Forum Transitorium_, begun by Domitian, but dedicated in the short reign of Nerva, and hence generally called the _Forum of Nerva_, on account of the execration with which the memory of Domitian was regarded. Up to the seventeenth century seven magnificent columns of the temple of Minerva were still standing, but they were destroyed by Paul V., who used part of them in building the Fontana Paolina. The existing remains consist of two half-buried Corinthian columns with a figure of Minerva, and a frieze of bas-reliefs.