Widely regarded as Mies van der Rohe's masterpiece, Crown Hall, completed in 1956, is one of the most architecturally significant buildings of the 20th century Modernist movement, and the start to the International Style of building. Crown Hall is considered architecturally significant because Mies van der Rohe refined the basic steel and glass construction style, beautifully capturing simplicity and openness. While designing Crown Hall, Mies stayed true to his famous words, "less is more" and he considered the building to be the best embodiment of that maxim.  Mies once described his creation as being "almost nothing." With WWII and the Great Depression leaving a large break in construction, Mies reconstructed curriculum to appreciate minimalism and to focus on using only what was necessary; an approach not yet favorable in most architecture schools of the time.
Centrally located on the campus of the Illinois Institute of Technology, two miles south of downtown Chicago, Illinois, the building houses IIT's school of architecture. The two-level building is configured as a pure rectangular form, 220 ft. by 120 ft. by 18 ft. tall. The enclosed space is column free with four six ft. steel plate girders welded to eight H-columns. These girders suspend the roof in a single plane to form a primary structure. While the lower level consists of compartmentalized rooms, the upper level occupies almost 50% of the total area of the building, but only includes one large, open classroom.
The design for Crown Hall is said to be derived from the Cantor Drive-In Restaurant which Mies van der Rohe had recently designed in 1945. Crown Hall is characterized by an aesthetic of industrial simplicity with articulated exposed steel frame construction. The lower 8 ft. of glass encircling the steel frame is a glazed transparency meant to allow for few outside distractions, while the upper 10 ft. is clear glass to allow more natural light in as well as viewing of the clouds and sky. This results in a delicate steel and glass facade enclosing an open plane. Mies called the Crown Hall a "universal space", because its design permits change in the function of the building while the architecture focuses on the permanence of the building's surroundings. Upon its opening, Mies van der Rohe declared it "the clearest structure we have done, the best to express our philosophy". One critic calls it the Parthenon of the 20th Century.
On March 27, 2012, Mies van der Rohe's 126th birthday, Google honored the architect and this icon of his achievement with a poetic doodle of Crown Hall.
In August 2005, a major renovation was completed by Krueck and Sexton Architects, rescuing the building from years of lagging maintenance, enhancing its accessibility and functionality, improving overall energy and environmental performance, and restoring Crown close to its 1956 appearance. The original 'Detroit graphite' lead paint was stripped from the structural steel and replaced with a lead-free black Tnemec urethane coating. The glazing was completely replaced with panes and stops that meet current wind load requirements. True sandblasted glass, original to the building but absent since a prior renovation, was installed in the lower panes. The entire travertine-paved south terrace was replaced. Interior wood partitions and storage lockers were refinished and resurfaced, and additional electrical and ethernet wiring was added to the main floor.