Jefferson National Expansion Memorial

World Monuments Watch
St. Louis, Missouri, United States

2014 World Monuments Watch

Conceived in the 1930s by Luther Ely Smith and constructed between 1963 and 1965 according to Eero Saarinen’s winning design, the Jefferson National Expansion Memorial soars over a carefully designed landscape, underground visitor center, and museum. The Gateway Arch feature of the memorial, often referred to as simply “the Arch,” consists of a stainless steel exterior and carbon steel interior and rises 630 feet above the ground. A unique tram system transports visitors to the observation deck at the top, providing an unparalleled vista of the American heartland. The Arch serves as a centerpiece of St. Louis and is often a locale for public gatherings, political rallies, cultural events, and other civic activities. Nationally and internationally, the Arch stands as a symbol of westward expansion in the United States and as an icon of mid-century modernism.

As is the case with many important examples of modern architecture, the preservation of twentieth-century materials and structural designs has proven challenging. The unusual shape and extreme height of the Arch compound these difficulties, as do economic trends that have led to decreased government funding for the stewardship of national monuments. The structure was included on the 2014 World Monuments Watch in order to encourage cooperation between the public and private sectors that would ensure the allocation of adequate expertise and resources to the preservation of this important landmark and national symbol.

Watch Day

Watch Day at the Jefferson National Expansion Memorial took place in October 2014 and included lectures about the reasons for the structure’s inclusion on the World Monuments Watch, as well as an exhibition about the Watch in the visitor center. Information tables were set up and members of the public were able to observe an investigation of the staining on the Gateway Arch.

Since the Watch

Staining on the Arch’s upper reaches was inspected in October 2014. It was found to be non-corrosive dirt unrelated to the structure’s stability, and it is no longer accumulating. In April 2015, we collaborated with the National Center for Preservation Technology and Training, the St. Louis chapter of the American Institute of Architects, and the Sam Fox School of Design & Visual Arts of Washington University in St. Louis to organize a three-day symposium called “Midcentury Modern: Materials and Preservation.” In addition to presentations of 24 papers, the event included a free public lecture, a poster session, and a participant tour of mid-century modern sites in St. Louis. A project designed to revitalize the site, which includes the cleaning of the stains on the Arch as well as plans for the expansion and update of the museum and trams, is scheduled for completion in the spring of 2017.


Last updated: May 2017.

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