Along the curved avenues and the diagonals the architectural design should avoid the building up of the thoroughfare structure by structure, each one following the whim of its owner or the struggle for novelty on the part of its architect. Without attempting to secure formality, or to insist on uniformity of design on a large scale, there should be a constant display of teamwork, so to speak, on the part of the architects. The former days when each architect strove to build his cornice higher or more elaborate than the adjoining cornice are giving place, happily, to the saner idea of accepting existing conditions when a reasonable line has been established. There is as much reason why façades should live together in harmony as there is for peace among neighbors. In the case of open spaces, effectiveness of architectural design is to be obtained only by a large unity in the entire composition. The harmonious treatment of the buildings facing the circle opposite the railway station in Rome and on the Place Vendôme in Paris, and the plan adopted for the plaza in front of the Union Station at Washington, all prove that an imposing effect can be produced by a unified and grandly simple design. In Paris when attempt was made to alter some of the houses in the Place Vendôme, the owners were forbidden to do so, because the proposed alterations would have spoiled the architectural symmetry of that circle. [Illustration: XCIV. PARIS. THE CHAMPS ÉLYSEÉS, FROM THE PLACE DE LA CONCORDE, SHOWING THE ARC DE TRIOMPHE IN VISTA.] [Illustration: XCV. PARIS. VIEW FROM THE ARC DE TRIOMPHE ALONG THE AVENUE DU BOIS DE BOULOGNE.] Chicago, being a comparatively new city, escapes one difficulty experienced in the re-formation of cities of the Old World; here there are no buildings possessing either historical or picturesque value which must be sacrificed in order to carry out the plans necessary to provide circulation for a growing metropolis. The absence of monumental structures, however, imposes other obligations on the city planner. All the boulevards of Paris were established on the models of the boulevards of Louis XIV., with two lines of trees bordering the driveways, and lines of houses on each side of the street, so that the mass of verdure almost entirely obscures the view of the façades. In the new streets the houses are to have a different system of alignment, so as to form a broken line which will admit of alternate masses of masonry, and masses of green. In this manner the boulevards will gain in artistic effect; while at the same time the line of the façades will be lengthened, thereby making the interior of the dwellings more healthful and agreeable. Much the same effect is produced in many Boston and some Washington apartment buildings, which are constructed on three sides of a court, leaving a mass of green open to the street.