July 25, 1942 Farm families out, construction moves in Project cost: $700,000 After the Douglas Aircraft Company announces plans to construct an assembly plant on 1,347 acres at Orchard Place, near the intersection of Mannheim and Higgins roads south of Des Plaines, work begins to demolish homes, level land and create a spur line of the North Western railroad at the site.

July 30, 1943 Douglas Aircraft plant dedicated The first C-54 Skymaster (then the U.S. Army's largest transport plane) built in the Douglas Aircraft factory (then the world's largest cargo plane factory) takes its maiden flight. Just 10 months after ground was broken on the main manufacturing building, the huge plant -- said by the company to be the largest timber construction in the world -- is finished. Four concrete runways are also ready on the site. (Chicago Tribune, July 31, 1943) ("Master plan of Chicago Orchard (Douglas) Airport," by Ralph Burke (January 1948) via Northwestern University Transportation Library)

Sept. 30, 1945 Douglas production ends After the end of World War II, the plant, which once employed 17,000 people, closes. Civic leaders urge Chicago officials to acquire the property, which could potentially double in size, for use as the city's main airport and note its location fits well into plans for a network of planned expressways. The assembly line in the Douglas Aircraft plant in Park Ridge, where wings are attached to the fuselage of big C-54 planes, is seen on July 7, 1944. (Douglas Aircraft Co. photo) (Chicago Tribune, Sept. 3, 1945)

Oct. 29, 1945 Unanimous decision: Former Douglas site should become city's main airport Project cost: $40 million After considering five locations, the airport selection board appointed by Chicago Mayor Edward Kelly picks this site, which would need to be purchased from the federal government, as the best choice for the city's postwar airport. The project's estimated $40-million price tag -- cheaper than a proposed lakeside airport and with room to expand, unlike Chicago Municipal Airport (now Midway International Airport ) -- would include the purchase of additional land to construct a pinwheel-like arrangement of 10 runways around a central administrative center. The following year, the city unveils its plan to create longer runways by adjusting the boundaries of the 5,230-acre (more than 6 square miles) tract. ("Master plan of Chicago Orchard (Douglas) Airport," by Ralph H. Burke (January 1948) via Northwestern University Transportation Library) ("Master plan of Chicago Orchard (Douglas) Airport," by Ralph H. Burke (January 1948) via Northwestern University Transportation Library)

March 22, 1946 City gets former Douglas site -- for free Project cost: None After posting an ad listing the property as available, the War Assets Administration hands over the 1,080-acre site to the city of Chicago -- while keeping 200 acres to be used by the U.S. Army for storage -- at no cost. But, there was a catch: If any atom bomb material were to be discovered at the site, then it had to be turned over to the federal government. Now the city could begin condemnation proceedings to acquire the additional property -- which included 2,300 lots, 63 farms, a small cemetery, a golf course, county school land and two county schools -- needed to build out the new airport. (Chicago Tribune, March 23, 1946) (Chicago Tribune, Feb. 26, 1946)

Feb. 10, 1947 New boundaries The city passes an ordinance expanding the footprint for the site, now called Chicago Orchard (Douglas) Airport, to 3,280 acres. (Chicago Tribune, Feb. 11, 1947)

Oct. 29, 1955 Passenger service begins Despite rain and low clouds, Trans World Airlines Flight 94 bound for Paris, then Cairo, was the first to depart with passengers from what was then the world's largest airport. The first passenger to board was Dorothy Marth, of Kankakee, who was heading to Paris to visit her husband, Weldon, a private in the U.S. Army who was stationed there. "I consider O'Hare's beginning as a long and firm step into the jet air line age, now upon us. We have the space for expansion for vast future developments that may now be entirely unguessed," Mayor Richard J. Daley said before 2,500 spectators on the second floor of the new passenger concourse. What did passengers not find when the airport opened? Restaurants, cocktail lounges and snack bars -- none were yet in place. Coffee, pre-made sandwiches and drinks were sold from vending machines. (Chicago Tribune historical photo, Oct. 29, 1955)

March 28, 1956 O'Hare annexed by Chicago This move allows the city to establish a police force and other services -- including construction of a new water main -- at the site. Deserted lobby of terminal reinforces mayor's argument that not enough traffic has been transferred to O'Hare. (Julius Gantter/Chicago Tribune) (Chicago Tribune, March 29, 1956)

Sept. 25, 1956 Fifth runway opens The 8,000-foot runway -- the first to be completed as part of an O'Hare expansion program -- had been completed for months, but had to wait for its lights to be connected to the control tower before opening. (Chicago Tribune, Sept. 26, 1956) (Chicago Tribune, Oct. 4, 1956)

Aug. 8, 1958 O'Hare becomes international When a TWA flight landed at O'Hare from Paris, its passengers were the first to be processed inside a customs depot that included immigration, public health and agricultural inspectors -- services that weren't previously available. (Chicago Tribune, Aug. 9, 1958)

Jan. 7, 1959 Airport's longest runway gets addition Project cost: $3 million Three years after its installation, O'Hare's fifth runway is extended to 8,838 feet long at a cost of $3 million. Other additions include a layer of concrete on top, a drainage system and a taxiway.

Aug. 31, 1960 Extension makes O'Hare runway longest civilian one in the U.S. A Lufthansa flight from Frankfurt, Germany, is the first to land on the 11,600-foot-long runway -- a length of more than 2 miles. (Chicago Tribune, Sept. 1, 1960)

Nov. 5, 1960 Northwest Expressway connects the Loop to O'Hare Now known as the Kennedy Expressway, the then eight-lane, 16-mile-long superhighway was expected to cut the drive time from the Loop to O'Hare down from an hour to 25 minutes with its 45 mph speed limit. Illinois Gov. William Stratton, center, is flanked by Chicago Mayor Richard J. Daley, left, and Cook County Board President Dan Ryan as they officially open the Northwest Expressway on Nov. 5, 1960. (Chicago Tribune historical photo) (Chicago Tribune, Nov. 6, 1960)

Jan. 17, 1962 Giant passenger terminal opens The black-and-white structure -- actually two separate 75-foot-long buildings connected by a not-yet functioning rotunda restaurant -- opened to the public one day after Mayor Richard J. Daley toured it. "We now have the greatest concentration of transportation facilities in the world," he said. "We are first in railroads, first in aviation, trucking, bus movements and the Great Lakes are now the high seas." Passengers -- including those aboard a United Airlines DC-8 that mistakenly arrived at the new terminal before it was fully operational -- could walk from the plane to the terminal via a covered ramp without going outside. Other features included ticket counters, luggage weighing stations, a telephone system and shops upstairs and a lower-level baggage area. A free shuttle bus would take passengers from their cars in a new but still-unfinished parking lot to the terminal buildings. Night view of one of the two new passenger terminals at O'Hare. This is the terminal for United, Continental, Northwest and Trans Canada airlines. Lower level is for handling of baggage. (Metro News Photos)

Aug. 10, 1962 Parking lot with 5,800 spaces debuts Project cost: $5 million The expanded lot added spaces for 3,000 more vehicles, making room for travelers and sightseers. The airport had become a big draw for folks checking out the airport, but whose vehicles took up spots intended for travelers. Now there were spaces available for both. The project finished a few months ahead of schedule due to good weather. (Chicago Tribune historical photo by John Austad, Aug. 10, 1962)

March 23, 1963 Chicago O'Hare International Airport dedicated Just eight months before his death, President John F. Kennedy arrived in Chicago not only to dedicate the city's airport but also to stump for Mayor Richard J. Daley's election for a third term just 10 days later. "Among airports, it is first in the nation, like so many other things about Chicago," Kennedy said. "Chicago has always been a crossroads of American transportation. That has long been a major cause of its growth and a reason for its very existence." President John F. Kennedy helps to dedicate a plaque honoring the memory of Lt. Cmdr. Edward H. O'Hare, on March 23, 1963. (Chicago Tribune historical photo)

March 25, 1963 Restaurants open with a feast Project cost: $6 million The $6-million rotunda building -- with circular glass walls and four dining rooms -- opens with a dinner in its upscale Seven Continents restaurant attended by Mayor Daley and more than 200 other civic leaders. Operated by Carson Pirie Scott & Co., Seven Continents is equipped to serve more than 20,000 meals each day to airport visitors and travelers. Entrees include live Maine lobster, Russian caviar and escargot, some flown in daily. Waiters, several of whom speak three languages, are also imported -- from Switzerland. Seven Continents restaurant. (Peoples Gas photo)

Dec. 16, 1966 Taxi bridge over highway in operation This improvement allows the largest jets at the airport to access the gates without the need for a lengthy circular taxi route. Runway 32R/14L also has been lengthened by a quarter mile. Aerial view showing the first United Airlines jet plane to cross the new runway at the overhead pass at O'Hare on Dec. 16, 1966. (Mike Rotunno aerial photo) (Chicago Tribune, Dec. 16, 1966)

June 28, 1968 World's largest air cargo center opens A three-level, 357,000-square-foot facility housing cargo operations for Continental and six other air carriers opens, joining five, smaller cargo centers on the property.

April 1970 Feds give city 26 acres to turn into parking Project cost: None The land, part of 360 acres used by the Illinois Air National Guard, Air Force Reserve and the Defense Contract Administration Agency, would be converted to parking.

May 4, 1971 New control tower is tallest in the U.S. Project cost: $2 million Standing 200 feet tall, the five-sided concrete tower is topped by a glass crown from which controllers can oversee an average of 1,900 flights per day. Fisheye view from inside the air control tower at O'Hare. (Metro News Photos)

Fall 1971 Seventh runway completed Project cost: $12 million This 8,070-foot strip gives the airport a second northeast-southwest runway that allows air traffic controllers to split up traffic and alleviate noise over Park Ridge and Des Plaines. O'Hare now has seven runways -- three of them 10,000 feet or longer to accommodate jumbo jets.

Dec. 16, 1972 5,000 additional parking spaces added The six-story structure's completion would mean 9,150 parking spaces -- with a maximum charge of $3 per day. Passengers could get to the terminal by using either a shuttle bus or tunnel. Though still under construction, the parking garage at O'Hare opened at noon on Dec. 16, 1972. Here, the first vehicles are seen entering the parking area as barricades are removed. (William Kelly/Chicago Tribune)

Jan. 7, 1973 Security checkpoints go into operation Everyone entering the terminal submits to electronic scanning devices -- checking for metal objects including guns, knives and bombs -- due to new federal anti-skyjacking regulations. In operation are 25 electronic screening devices for passengers, 11 X-ray units for carry-on luggage and several hand-held metal-detecting devices. This concourse at O'Hare is said to be "sterilized." Beyond this checkpoint lie the boarding gates for American, Delta, Allegheny and North Central airlines. (Michael Budrys/Chicago Tribune historical photo 1973)

Feb. 9, 1973 On-site hotel opens Project cost: $25 million With 10 stories and 979 rooms, the O'Hare International Tower Hotel is built to suppress jet noise due to its design of thick floor-to-ceiling windows, thick walls containing acoustical batting and heavy draperies. Topping out ceremonies for the new O'Hare International Tower Hotel on June 14, 1972. (William Kelly/Chicago Tribune)

Jan. 18, 1980 Becomes city's official weather recording site Midway was the city's official weather observation location for nearly 38 years -- from July 1, 1942, through Jan. 17, 1980. O'Hare, which had been a weather recording site since Oct. 30, 1958, then took over this designation, which continues today.

June 1, 1984 Delta terminal opens Project cost: $115 million Comprised of a 391-foot addition to Terminal 3 and a 740-foot concourse, the complex is the first new passenger area since the airport opened 22 years earlier. The project is part of the first phase of the airport's modernization program. (Chicago Tribune, May 23, 1984)

Sept. 3, 1984 'L' service arrives Project cost: $196 million After a two-year delay, the final leg of the line -- 2.6 miles from River Road to the airport -- connects the Loop to the airport. Mayor Harold Washington and jazz great Dizzy Gillespie, who then played "Take the 'A' Train," ride the inaugural train to O'Hare. The full 17.5-mile route takes 35 minutes and costs 90 cents. A flag-waving Mayor Harold Washington joins CTA Chairman Michael Cardilli and Gov. James Thompson at ceremonies inaugurating the final leg of the CTA's rapid transit line extension to O'Hare on Sept. 3, 1984. (John Dziekan/Chicago Tribune) (Chicago Tribune, Aug. 31, 1984)

March 15, 1985 Temporary international 'Terminal 4' debuts Project cost: $30 million Carved out of the ground floor of the airport's parking garage, this space would be a temporary replacement for the dingy, crowded, original domestic terminal built 34 years prior, which was not handicap accessible, had an inadequate baggage facility and had a troublesome security layout. Plans were to build a new international terminal within five years. With no direct access to aircraft, passengers would be bussed from the terminal and access planes via portable stairways. The few seats that were available were occupied at O'Hare's temporary international terminal on April 1, 1985. (Walter Kale/Chicago Tribune) (Chicago Tribune, March 12, 1985)

Aug. 4, 1987 United terminal opens Project cost: $540 million The Helmut Jahn -designed glass and aluminum complex includes two buildings connected by an underground walkway featuring a 744-foot flashing neon sculpture, galactic synthesizer music and moving sidewalks. The 85-acre facility -- which would include 42 gates upon its completion in December 1988 -- also includes a $38 million, computerized baggage-handling system that can process 480 bags a minute. A look down the concourse of United Airlines' new terminal at O'Hare in 1987. (Carl Hugare/Chicago Tribune photo) (Chicago Tribune, Aug. 3, 1987)

May 10, 1990 American Airlines' terminal dedicated Project cost: $345 million The 13 additional gates would help the airline handle its 450 flights leaving O'Hare each day. People walk through the American Airlines concourse at O'Hare on Aug. 14, 1991. (Hank DeGeorge/Chicago Tribune)

June 1992 Communications center begins operation Project cost: $40 million Located underneath the parking garage, this facility could be the most important part of the airport that passengers will never see. Police, fire and airport security personnel can coordinate their efforts in response to emergencies including data breaches, accidents, sick passengers, hijackings and catastrophic crashes. Staffers also can detect when any of the 37,000 computerized passes issued to airport workers are used to access sensitive areas.

May 27, 1993 International Terminal unveiled Project cost: $618 million The 1.2 million-square-foot, glass-and-steel building with dramatic, curving roof and skylights is almost complete following more than two years of construction. This facility, officially named Terminal 5, includes 21 gates, 156 ticket counters and is estimated to handle 4 million passengers annually. It's the last project of a $2 billion O'Hare revitalization and expansion program begun a decade earlier. At night, the lighted ticketing pavilion on the top level of the International Terminal is a glowing beacon to drivers approaching on the highway on May 20, 1993. The terminal opened to incoming flights May 27, 1993. (Charles Osgood/Chicago Tribune) (Chicago Tribune, May 5, 1993)

May 1993 People mover gets around Project cost: $127 million The computerized, driverless Airport Transit System -- made up of 13 45-foot-long cars in configurations of two or three -- connects the airport's two long-term parking lots and each of the terminals on a 2.7-mile-long track. Rubber wheels keep the trains' movement quiet and speedy at up to 50 mph. (Chuck Berman/Chicago Tribune) (Chicago Tribune, May 6, 1993)

July 1993 Iconic toilet seat covers installed Project cost: $350,000 It's just a layer of plastic that fits between the surface of a toilet seat and the person sitting on it, but it would become an iconic feature of the airport's 600 toilets. With the push of a button, a small electric motor advances the plastic sleeve around the seat and moves a fresh piece of plastic in its place. (Courtesy of Hygolet Marketing Department)

October 1996 State-of-the-art tower debuts Project cost: $22 million The glass-and-steel tower -- which is as tall as a 26-story skyscraper -- opens with advanced radar and telecommunications equipment for its controllers at the world's busiest airport. The "cab," the room where the controllers work, is the largest in the U.S. at 1,015 square feet. The 260-foot tall control tower at O'Hare is clad in a blue-green glass that reduces the tower's visual bulk. It replaces a shorter, existing one. (Chuck Berman/Chicago Tribune)

May 1997 'Hush house' added to combat noise Project cost: $2.1 million Nightly required aircraft engine maintenance tests, known as ground run-ups, include jets with no passengers aboard revving their engines at full power for up to 45 minutes at a time. It's not popular with those who live near the airport. To help combat this type of noise, the airport installs a huge, three-sided contraption -- called a hush house -- that's made of heavy-gauge galvanized steel and outfitted with noise-absorbing acoustical panels. It's the first one built at a commercial airport in the U.S. A jet leaves the "hush house" at O'Hare after checking its engines on May 1, 1997. (Phil Greer/Chicago Tribune)

Nov. 20, 2008 North control tower opens Project cost: $65 million The 255-foot tower is part of the $15 billion airport expansion project, which also includes a new runway. Since controllers in the airport's main tower can't see the west end of that runway, this new tower -- with four controllers and one Federal Aviation Administration supervisor assigned -- was needed. Runners glide by the new control tower still under construction during the "Athens Sister City Shuffle 5K on the Runway" race on the tarmac of the new runway at O'Hare on Sept. 21, 2008. (Nancy Stone/Chicago Tribune) (Chicago Tribune. Nov. 27, 2006)

Nov. 20, 2008 First new runway in 37 years added to operations Project cost: $565 million As part of a $15 billion O'Hare Modernization Program to replace the airport's outdated layout of intersecting runways with a parallel runway system, 9L/27R is designed to reduce delays. 9L-27R is the first new runway at O'Hare since 1961 and is seen here Nov. 20, 2008. (Chuck Berman/Chicago Tribune) (Chicago Tribune, Nov. 20, 2008)

Summer 2012 Disinterment of 1,494 bodies complete Project cost: $17 million In 2010, the city took over a 5-acre parcel of land on the west side of the airport intended for future runways. This land also included a 2-acre burial ground, St. Johannes Cemetery, established by a church of German pioneers in 1849. As graves were exhumed, extensive genealogical reports were used to identify next of kin, who could decide where their ancestors would be relocated. Following a lengthy eminent domain lawsuit, the city purchased the property from St. John United Church of Christ in Bensenville for $1.3 million in December 2012. Stan Steele rides a lawnmower past grave markers at St. Johannes Cemetery in Bensenville as a plane prepares to land at O'Hare in 2003. (Carl Wagner/Chicago Tribune) (Chicago Tribune, March 22, 2011)

Oct. 17, 2013 The cemetery runway' opens O'Hare's widest runway, 10 Center/28 Center, becomes the only strip at the airport able to accommodate four-engine superjumbo jets. At 10,800 feet long, it's just the second runway built since the expansion project began eight years earlier. A United plane arrives on the newest runway, 10C/28C, at O'Hare International Airport on Oct. 17, 2013. (Alex Garcia/Chicago Tribune) (Chicago Tribune, Sept. 28, 2008)

Oct. 15, 2015 Third east-west runway since 2008 begins operation Project cost: $516 million Opening with a taxiway, 10 Right/28 Left would be used exclusively for planes arriving toward the east until 10 p.m. daily. The runway, which aligns with Irving Park Road in Bensenville, sits several miles from the passenger terminal complex, which means it would take an average of 20 minutes for aircraft to taxi to the gate. An American Airlines plane sits near the new 10R/28L runway at O'Hare on Oct. 15, 2015. (Stacey Wescott/Chicago Tribune) (Chicago Tribune, Jan. 31, 2016)

Jan. 30, 2016 Sixth east-west runway to be built Project cost: About $650 million The city strikes a deal with major airlines to build the final runway envisioned in the airport's modernization program. The $1.3 billion deal includes new taxiways and de-icing pads, too, but no additional gates, which American Airlines and United Airlines have resisted due to potential competition. "One way in the past to measure O'Hare was busiest," Mayor Rahm Emanuel says during the plan's formal announcement. "That's one measure. My goal is best. And that's 'O'Hare 21,' which is what I'm naming this, but everything we're going to do is preparing O'Hare to be the economic engine, job-growth engine for the 21st century." Construction on the 11,245-foot-long runway, named 9 Center/27 Center, begins in August 2016. (Chicago Tribune, Dec. 4, 2017)

March 15, 2018 Single largest, most expensive O'Hare revamp gains steam Project cost: $8.5 billion A state-of-the-art global terminal, dozens of new gates and several additional concourses are part of an eight-year, $8.5 billion deal to revamp the 73-year-old airport. Mayor Rahm Emanuel seeks to leverage the May expiration of the airlines' 35-year lease to secure from the carriers higher fees and charges to help bankroll the ambitious project. He also strikes a deal with American Airlines to speed up the construction of three new gates in a successful effort to get the airline to drop its opposition to the project. The plan sails through its first test as the City Council adopts an ordinance allowing for new lease and use agreements for the gates at O'Hare to pay for the project. (Chicago Tribune, Feb. 26, 2018)