By Joe Frey

Looking at them at once, it may be hard to believe that the Monadnock Building and the Rookery were both designed by the same firm, Burnham & Root, with construction of the former starting in 1891, just a year after completion of the latter. The powerful Monadnock, totally devoid of the Rookery’s rich ornament, gives way to a stark, austere, almost Egyptian-like pylon. Eight feet thick below the sidewalk, and over six feet thick at the base, the load-bearing masonry walls narrow to a foot and a half as the load lessens with the height At the top, the walls mirror the flare at the base, curling into an overhanging cornice. Despite its load-bearing design — insisted upon by the developer — the Monadnock was, for a short time, the tallest office building in the world and is still the tallest occupied load-bearing building in the world. It could have been taller — the Great Pyramids of Gaza are twice as tall — but the added thickness of the walls required to go higher would have reduced the rentable space, rendering the building economically unfeasible.

Ornament here is reduced to the rhythm of the projecting bays and the curved cornice, made elegant by slicing the corner of the building on a bias, an effect called chamfering. The result is an unadorned tripartite composition, accentuated by the flare of the base, the projection of the bays and the seamless transition to the cornice. But the Monadnock is actually two buildings, the northern half described above. The southern half was designed by Holabird and Roche and completed in 1893, and is itself almost two separate buildings. The southernmost quadrant of the building, unlike the other three, was constructed with a skeletal frame, rather than with load-bearing walls. Yet both portions of this half of the Monadnock are clad in Beaux-Arts ornament, ironically putting historic decoration over the more modern structural system, while in the northern half of the building the archaic load-bearing walls are left unadorned in the more modernist aesthetic.

Inside, a long concourse, still lit with period light bulbs, runs the length of the building, with much-needed added light provided by windows dividing the corridor from the stores fronting the street. Though the cast aluminum railings of the first-floor stairways are reproductions, the originals, also of aluminum, were a rare decorative application of this then exotic metal; its use was another way for the developer and architects to convey richness in order to attract the most desirable tenants.