Which building demonstrates the combination of classical elements with modern construction techniques in Chicago?

The Monadnock Building is notable for its unique architectural style that beautifully merges classical elements with modern construction techniques. Designed by Holabird & Roche and completed in the 1891, this structure embodies the transition from traditional masonry to the use of steel frame construction, which was becoming increasingly popular during that era.

The building's design showcases a robust exterior with its red brick and terra cotta detailing, elements often associated with classical architecture. Additionally, the Monadnock's height and form reflect the principles of modern architecture, emphasizing function and structure. This combination is particularly significant, as it represents an important moment in architectural history where traditional styles began to incorporate new construction methods, leading to innovations in the design of urban skyscrapers.

The Willis Tower, Tribune Tower, and Art Institute of Chicago, while all important landmarks in Chicago, do not exemplify the same blending of classical and modern styles as effectively as the Monadnock Building. The Willis Tower is primarily a modernist structure, the Tribune Tower incorporates various historical styles inspired by Gothic architecture, and the Art Institute focuses on classical Beaux-Arts design elements rather than innovative construction techniques of that transitional period.