The oldest stadium now employed by an N.F.L. team is Chicago’s Soldier Field, opened in 1924, where the Bears are scheduled to face the Washington Redskins on Sunday. (Runner-up is the 58-year-old Lambeau Field, home of the Bears’ ancient rival, the Green Bay Packers.)  The durability of Soldier Field, hard by Lake Michigan, is particularly striking when you ponder how many N.F.L. stadiums are demolished as obsolete after three or four decades of use. Soldier Field’s longevity is the result of the stadium’s commanding city location, its timeless original architecture, the respect for its long history and its controversial transformation in 2002-2003 to meet the urgencies of the 21st century.  In contrast with most other N.F.L. stadiums, Soldier Field was not principally designed for professional football — which was embryonic in the early 1920s — but instead with broader and grander goals, including the city’s hope for a Chicago Olympics (which never came).  As Liam T.A. Ford wrote in his 2009 book on Soldier Field (University of Chicago Press), Chicago boosters wished to “outrival Paris” and “build the largest, most beautiful public arena in the world.”Their mayor, William Thompson, known as Big Bill, called for a vast 150,000-seat stadium, which would honor Chicago’s fallen World War I soldiers, exceeding what “the Romans had ever built.”  In its earliest incarnation — conceived by the firm Holabird & Roche, which won an architectural competition, and unveiled with a theatrical re-enactment of Chicago’s response to its ruinous Great Fire of 1871 — the Greek Revival stadium offered less than half the seating Thompson had hoped for. It hosted sundry sporting events — including track meets, college and high school football games, the “long count” boxing match between Jack Dempsey and Gene Tunney of 1927 — as well as signal moments in American political history.  It was at Soldier Field that the trans-Atlantic aviator Charles Lindbergh rallied a raucous crowd in 1940 against engagement in the war against Adolf Hitler, where Douglas MacArthur in 1951 denounced President Truman’s strategy in the Korean War after Truman fired him as United States commander, and where the Rev. Dr. Martin Luther King Jr., in the mid-1960s, demanded Chicago’s desegregation. During the 1968 Democratic convention, Mayor Richard J. Daley reserved the stadium for a possible 60th birthday celebration for President Johnson, but when anti-Vietnam War protesters surged into Grant Park and were confronted by the Chicago Police, L.B.J. was told to stay on his Texas ranch in safety.  For almost half a century, Soldier Field did not attract much pro football. (The Bears, for instance, faced the Packers and the Chicago Cardinals there in 1926, and the short-lived Chicago Rockets used the stadium in the late 1940s). It is hard to imagine, in retrospect, that for 49 years, the Bears relied on the baseball-friendly confines of Wrigley Field. (Attending a Bears game there at age 6, even I could figure out that Wrigley had not been built for football.)  By 1970, having long outgrown Wrigley, the Bears felt pressure from the N.F.L. to find a larger edifice. The owner, George Halas — “Papa Bear” — who disdained the decay of Soldier Field and its difficult sight lines for football, negotiated to share Dyche Stadium at Northwestern University, in Evanston, Ill., but the deal was opposed by Big Ten officials and the local city council. Lacking immediate alternatives, Halas started his team’s 1971 season against the Pittsburgh Steelers at Soldier Field.  In the early 1970s came new urban, spare-tire-shaped, Brutalist concrete stadiums like Riverfront in Cincinnati and Three Rivers in Pittsburgh. (Both have since been razed.) Mayor Daley floated schemes to construct a new stadium for the Bears — some with a dome or partial dome — but insisted that Soldier Field could be retooled far more cheaply.  Eager to prod Daley into building a new stadium, Halas warned that if the mayor dragged his feet, the Bears might be forced to relocate in the suburbs, as the former Boston Patriots had done. Arlington Heights, Ill., was one locale mentioned. Daley threatened back that if Halas dislodged the Bears, he would sue to prevent the team from using his city’s name. According to the Ford book, Daley was said to have told Halas, tauntingly, that in that case, “I wonder how many people will come out to see the Arlington Heights Bears, George.”  The Bears stayed, but help was still badly required for what a 1975 Chicago Tribune editorial called “the great white elephant by the lake.” In 1995, after years of bargaining, the team’s president, Michael McCaskey — Halas’s grandson — raised the possibility of moving the Bears to Gary, Ind. Mayor Richard M. Daley — son of Halas’s old sparring partner — suggested at one point that the team try Alaska.  Finally the firm of Wood + Zapata and the architect Dirk Lohan — grandson of the renowned modernist Mies van der Rohe — designed a postmodern structure to be built within and above Soldier Field’s old neoclassical shell, and the project was completed in 2003. The new design added luxury seating and updated facilities but reduced capacity to 61,500 seats, which makes it too small, for example, to meet an N.F.L. requirement to host a Super Bowl. The Tribune’s architecture critic, Blair Kamin, wrote, “With its spaceship-like seating bowl crammed between the stadium’s legendary rows of Doric columns, the stadium is Klingon meets Parthenon, an architectural close encounter of the worst kind.”  Kamin was far from alone in his criticism. Others thought the new stadium looked like “a giant egg in a giant egg cup” or “a fat man trying to wedge himself into a skinny man’s shorts.”  But The New York Times’s architecture critic at the time, Herbert Muschamp, called the newly remade Soldier Field a “dynamic remodeling,” adding that “clients need to be less fearful of provoking criticism.” Using what might be construed as a football metaphor, Muschamp went on to write: “It is inherently aggressive to move things forward. Those with the courage to do so should not be surprised if they become targets of others’ aggression in return.”  Michael Beschloss, a presidential historian, is the author of nine books and a contributor to NBC News and “PBS NewsHour.” Follow him on Twitter at @BeschlossDC.  The Upshot provides news, analysis and graphics about politics, policy and everyday life. Follow us on Facebook and Twitter. Sign up for our newsletter.  A version of this article appears in print on December 13, 2015, on page SP8 of the New York edition with the headline: Still Standing in Chicago. Order Reprints| Today's Paper|Subscribe
The stadium, which has survived decay and suggestions of demolition, was conceived with grand goals for Chicago’s place in the world.