Few structures are as synonymous with their locations as the Jefferson National Expansion Memorial Arch in St. Louis. Designed by Eero Saarinen with a landscape by Dan Kiley and completed in 1965, the Arch is central to the identity of St. Louis. And yet while the glinting form still draws a million tourists each year, the structure adds little vitality to the city’s downtown.

Five teams, including leading architecture, landscape architecture, and engineering firms from across the United States and Europe, have been working on ambitious plans to re-envision the memorial and grounds as a dynamic urban park, revitalizing both its relationship to the city as well as its cultural, environmental, and educational roles as a national park. The results were unveiled today by the CityArchRiver 2015 Foundation, which sponsored the competition.

The Arch grounds are currently isolated on three sides and bounded on the other by the Mississippi River. To the north, the site is delimited by the Eads Bridge and parking structures; to the west, by Memorial Drive and I-70, severing the connection to the Old Courthouse and the Gateway Mall, which includes the newly renovated and highly popular CityGarden; and to the south by the MacArthur Bridge and its approaches. The best place to view the Arch is in neighboring East St. Louis, Illinois, but that waterfront is currently underdeveloped.

The five multi-disciplinary teams grappling with this complex site are led by Michael Van Valkenburgh Associates, Weiss/Manfredi, SOM Chicago with Hargreaves Associates and BIG, Behnisch Architekten, and PWP Landscape Architects with Foster + Partners and Civitas. The teams were selected from a roster of nine contenders . The winning team will be announced on September 25. Organizers hope construction will be complete by October 28, 2015, the 50th anniversary of the day the keystone section of the Arch was secured in place.