The Jefferson National Expansion Memorial includes the 630-foot-tall stainless steel Gateway Arch, designed by Eero Saarinen as a symbol of St. Louis's role as the gateway to the west; a tram carries visitors to a small observation deck with 16 windows at the top, the structure holds up to 160 people, cost $13 million to build, was begun on February 12, 1963, completed on October 28, 1965, and was designed to flex in an earthquake or sway as much as 18 inches while remaining grounded and insulated from the many lightning strikes it receives each year. Nearby, the Old Courthouse stands on land given to St. Louis County in 1816 by Auguste Chouteau and Judge John B.C. Lucas on the condition that it be used for the county courthouse; the original building went up in 1828, later additions and remodeling began in 1839, and in 1861 a cast-iron Italian Renaissance dome modeled after Saint Peter's Basilica in Rome was installed and proved sound despite criticism. Beneath the Arch, the Museum of Westward Expansion contains artifacts and exhibits on Lewis and Clark, the Corps of Discovery, pioneers, and Native American cultures in the American West. The MLK Bridge, opened in 1951 as the Veterans Memorial Bridge, is the sixth largest and longest cantilevered truss bridge in the United States and the largest such bridge over the Mississippi; U.S. 40 and U.S. 66 crossed it from 1955 to 1967, it was renamed in 1968 for Doctor Martin Luther King, Jr., and after falling into disrepair it was taken over and rebuilt by the St. Louis Port Authority in the late 1980s. The Floodwall Art Project is a seven-foot-tall, 150-foot-long tile mural designed by ceramic artist Catherine Magel with help from about 1,500 youths and adults from at least six North St. Louis communities; it traces the history of the natural world from microscopic life to sea life, earth creatures, and migrating birds, includes birds made by grieving children who placed private messages inside them as a metaphor for letting go, fostered community pride and care for the site, and was supported by groups including Americorps, Confluence Greenway, the Missouri Arts Council, and other corporations. The Great Rivers Greenway District leads development of the River Ring, a region-wide system of interconnected greenways, parks, and trails that will link two states across 1,216 square miles; formerly called the Metropolitan Park and Recreation District, it was established in November 2000 after passage of Proposition C in St. Louis City, St. Louis County, and St. Charles County, Missouri.
