I have long been fascinated by the modernist Sheraton Hotel in downtown Denver. It was constructed as the Denver Hilton Hotel in 1960 as part of the Courthouse Square urban renewal project by I.M. Pei & Associates, and is generally regarded as a modernist masterpiece.
The hotel was one of three buildings in the Courthouse Square complex, which included a May – D&F Department Store and a hyperbolic paraboloid structure. All three were designed by I.M. Pei & Associates, with architect Araldo Cossutta the designer of the hotel, and Henry Cobb the designer of the store and plaza. The plaza, which was also known as Zeckendorf Plaza after the developer of the site, contained a seasonal outdoor skating rink. It was meant to be Denver’s answer to New York’s Rockefeller Center. Historic photographs of the department store and hyperbolic paraboloid structure can be found here and here in the digital collection of the Denver Public Library. The Denver Eye also has some great historic photos and drawings of the Court House Square complex. Sadly, in the 1990s, the Adam’s Mark Hotel, which at the time owned the Hilton, decided to enlarge the hotel by adding a conference complex on the site of the May – D&F Department store. The store and the hyperbolic paraboloid were demolished in 1995, much to the frustration of local preservationists.
(An interesting tidbit: Court House Square was built on the site of the old Arapahoe County Court House, which was demolished in the 1930s after Denver County became autonomous from Arapahoe County. Historic photos of the incredible court house building can be found here.)
As I mentioned above, the Denver Hilton Hotel was designed by Araldo Cossutta, a partner at I.M. Pei & Associates. Early in his architecture practice Cossutta studied in the atelier of Le Courbusier, whose influence is evident in the design of the hotel. The hotel was a unique contribution to the downtown skyline, and Zeckendorf Plaza was beloved by several generations of Denverites and architecture fans. As a result, I.M. Pei & Associates won several awards for the design of the hotel and the department store complex upon their completion.
The hotel was constructed with pre-cast panels of concrete known as cast stone. The cast stone for the hotel was made using aggregate collected during excavation of the site, in part because Pei believed “a building should come from the earth”.  The large panels were fabricated in Salt Lake City and shipped to Denver for construction on site.
Elaborate grids of cast stone give the building the illusion of greater height than its twelve stories. The base of the building consists of recessed plate-glass windows set between concrete piers, which makes the building look as though it is floating above the street. The second story, which houses public spaces and conference rooms, is differentiated by tall vertical slits of glass set into a projecting cast stone framework. The windows of the next two or three stories are set behind an elaborate Mo-Sai grid, while the upper story hotel floors have larger, rectangular windows set in a vertical orientation. The building is capped by a tall penthouse floor with tall, wide windows set behind a low, concrete railing. All of the windows are recessed behind the cast stone grid, which provided shade to the west-facing primary façade.
In addition to providing shade, the grid pattern cleverly hides the joints of each pre-cast panel, giving the impression that the entire building is one monolithic structure. Vertical joints can be seen running up the façades, but horizontal joints are less obvious. You can barely make them out below some horizontal elements in the photo below.
If you stroll around the building, you might notice that in some locations you can see clear through the second floor to the masonry on the opposite side of the building.
Although the department store and hyperbolic paraboloid structure on the other side of Court Street were demolished, at least we can still admire this modernist masterpiece.
Source:  Paglia, Michael, Rodd L. Wheaton and Diane Wray, Denver: The Modern City. Denver: Historic Denver, Inc., 1999. p. 34