Chicago O'Hare International Airport

The opening of Chicago Municipal Airport (now Chicago Midway International) in 1926 soon brought the city to the realization that more space would be needed, as it was only one square mile in size. And while some sites were explored, little progress was made initially. In WWII, the northeast corner of what is now O'Hare housed a Douglas manufacturing plant, which built C-54 Skymasters for the war. The plant was 2 million square feet, and it was responsible for having built 655 C-54s, over half of all built. As such, there was a need to create easy access for the workforce to get back to the city while keeping the plant safe. There was also an airfield on site from where the C-54s flew out, which had four 5,500-foot runways, and it was known as Douglas Airport. At the conclusion of WWII, the contract with Douglas ended, and the company moved its manufacturing to its headquarters in Santa Monica, California. The airport was then renamed Orchard Field Airport and was assigned the IATA code ORD. In 1949 the airport was once again renamed after Edward "Butch" O'Hare, the Navy's first Medal of Honor recipient in WWII. However, the code ORD was kept, meaning that O'Hare is one of the few airports with a code that is irrelevant to its name and location. As the airport had no scheduled airline service, the United States Air Force used the airport extensively during the Korean War. It was used as a fighter base, and the 62nd Fighter-Interceptor Squadron flew F-86 Sabres from the base from 1950 to 1959. As commercial business was picking up by 1960 and the need to fly fighters had dwindled, the Air Force turned the base over to the Continental Air Command, who then used the base to station reserve and Air National Guard Units there. The base remained until it was closed by agreement on April 1st, 1997, with the land turned over to the Chicago Department of Aviation. As for commercial aviation, Chicago mayor Edward Kelly appointed a board to choose a new airport site in 1945 with an eye toward the future. The board decided that what was Orchard Field at the time was the ideal location and bought most of the land from the federal government in 1946 (with the exception being the small amount of land that was reserved for military use, which also maintained the right to use up to 25% of the airfield's capacity for free). A plan was developed by Ralph H. Burke by which the airport would use "split-finger terminals," whereby a terminal building would attach to "airline wings," which were essentially concourses with gates for planes. The plans also called for direct highway access to the front of terminals, direct railway access from downtown, and underground refueling capabilities, all of which are done at airports around the world today. In 1958 O'Hare was the site for the world's first jet bridge while successfully adopting slip-form paving, which allowed for seamless concrete runways. While $25 million was invested in the airport, airlines were initially hesitant to move from Midway (as improvements were still ongoing), which meant that while service had already begun in 1955, initial growth was slow. The Official Airline Guide of 1957 listed 36 weekday departures, which paled in comparison to Midway's 414. Slowly, the improvements began taking hold. In 1948 the first international terminal was opened, and the next year the airport expanded to 7,200 acres with new terminals, parking, hangars, and more. The expressway link to downtown Chicago was completed in 1960, and in 1962 the new Terminals 2 and 3 (designed by C. F. Murphy and Associates) opened. These improvements, along with the rise of the jetliner, attracted the airlines to O'Hare. Midway did not have adequate space for the runways that the new Boing 707s and Douglas DC-8s required. As airlines did not want to split their service, they moved operations from Midway, and by July 1962, all scheduled airline flights (besides Chicago Helicopter Airways) had moved to O'Hare. The airport quickly began processing 10 million people a year (a number which doubled within two years and kept rising after that), making it the world's busiest airport. It would keep that distinction until 1998. Following airline deregulation, the 1980s saw several airlines move their hubs from O'Hare elsewhere, as they were losing money and unable to compete with United and American properly. These included TWA (moved their hub to St. Louis), Northwest (preferred a Detroit and Minneapolis-based network), and Delta (focused its upper Midwest operations in Cincinnati). As for the two airlines with major hubs, United had a new Terminal 1 built on the site of the original Terminal 1. The new terminal, developed between 1985 and 1987, had two concourses and 50 gates. It became known for its design by Helmut Jahn, with curved glass forms and a connecting underground tunnel between Concourses B and C. As for American, they expanded their existing facilities in Terminal 3 between 1987 and 1990. The flag-lined entrance hall to Concourses H/K is a prominent feature of the expansion. The demolition of the original Terminal 1 forced a temporary relocation of international flights into "Terminal 4" on the ground floor of the airport's central parking garage. International travelers were bussed to their flights from there. This ended with the completion of the 21-gate Terminal 5 in 1993 (it was called the International Terminal at the time). The new terminal brought about the need for the creation of the "People Mover" by the Airport Transit System, which connected the terminal core with the new terminal along with remote rental and parking lots. As for its runways, O'Hare initially had four in 1955; in 1956, the 8,000-foot 14/R opened (it was later extended to 11,600 feet in order to enable nonstop flights to Europe); runway 9R/27L (now 10L/28R) opened in 1968; runway 4R/22L opened in 1971. These runways were angled to allow takeoffs into the wind. However, they were inefficient and somewhat dangerous, as the runways intersected. This led to many flight delays, and O'Hare was rated one of the worst-performing airports in the country on official reports in the late 90s. This led to a need to modernize, and the Chicago Department of Aviation committed to the O'Hare Modernization Plan (OMP), which involved the complete reconfiguration of the airfield. Approved by the FAA in 2005, there were to be four new runways, a lengthening of two existing runways, and the decommissioning of three old runways. This would result in O'Hare having six parallel runways and two crosswind runways. Due to legal issues involving suburbs fearing the noise implications and survivors of people interred in a cemetery the city proposed to relocate, the OMP was severely delayed, only concluding in 2021.

The airport is located 17 miles northwest of the Loop business district in Chicago. 

• There is a four-story high, 72-foot-long Brachiosaurus Dinosaur skeleton in Terminal 1, Concourse B. It was excavated in 1900 by Elmer Riggs. 
• The tunnel connecting Concourses B and C in Terminal 1 feature a 745-foot-long neon kinetic light sculpture designed by Michael Hayden called "The Sky's The Limit." As the sculpture includes 23,600 square feet of mirror, the neon is reflected for over a mile. 
• Directly across from Security Checkpoint 3 in Terminal 1 is "Jet Trails" by Guy Kemper, a 50-foot-long, 12-foot-high sculpture comprised of blown glass, which is suspended onto the window mullions. 
• O'Hare is considered the world's most connected airport, with 242 nonstop flights to destinations in North America, South America, Europe, Asia, Africa, the Middle East, Oceania, and the North Atlantic region. 
• O'Hare has an apiary, which was built in 2011 (the world's first airport to do so). It hosts 75 hives and as many as a million bees every summer. 
• There is a new Terminal Area Plan called O'Hare 21. Plans include two all-new satellite courses, the increasing gate count from 185 to 235, the addition of over 3 million square feet to the airport's terminals, and much more. O'Hare 21 is budgeted to cost $8.5 billion and is scheduled for completion by 2028 (although that estimate was from October 2020 and may have changed due to COVID-19).