1673
French-Canadian explorers Jacques Marquette and Louis Jolliet pass through the area that will become Chicago.
1682
French explorer René Robert Cavelier, Sieur de la Salle, passes through Chicago en route to the mouth of the Mississippi River.
1683
French Jesuits establish Fort de Chicago, the area's first true European settlement.
1696
Jesuit missionary Francois Pinet founds the Mission of the Guardian Angel. It is abandoned four years later.
1705
Conflicts develop between French traders and the Fox tribe of native Americans. Fort de Chicago is abandoned.
1795
Six square miles of land at the mouth of the Chicago River are reserved by the Treaty of Greenville for use by the United States.
1779
Haitian immigrant Jean-Baptiste Point du Sable establishes Chicago's first permanent settlement near the mouth of the Chicago River.
1796
The Potawatomi Indian wife of du Sable delivers Eulalia Pointe du Sable, Chicago's first recorded birth.
1803
U.S. Army constructs Ft. Dearborn near the mouth of the Chicago River.
1812
Ft. Dearborn is destroyed following a conflict with native Americans.
1816
Ft. Dearborn is rebuilt.
1818
Illinois is admitted to the union.
1830
First plat is drawn of the town of Chicago.
1833
Chicago incorporates as a town of 350 people. Town limits are bounded by Kinzie, DesPlaines, Madison and Kinzie streets.
1837
Chicago incorporates as a city of 4,170 people. William B. Ogden is elected its first mayor.
C. D. Peacock jewelers is founded. It is the oldest Chicago business still in existence today.
1844
The city's first public school is built near Madison and State streets.
1848
"The Pioneer," Chicago's first locomotive, arrives on Galena and Chicago Union Railroad tracks along Kinzie Street.
The city's first City Hall is erected on State Street.
1850
Gas lamps are erected on Lake Street and several adjacent blocks.
1851
The Chicago area's first university, Northwestern, is founded.
1855
Mayor Dr. Levi Boone organizes the city's first police department.
A public demonstration against the city's prohibition of beer sales on Sunday results in more than 60 arrests.
1856
Ft. Dearborn is demolished.
1860
Chicago hosts its first political convention. The Republican Party nominates Abraham Lincoln for the U.S. presidency.
1863
Mercy Hospital becomes the first hospital in Illinois.
1865
Union Stock Yards open on Christmas day.
1867
Chicago's first water tunnel is completed.
1869
The Chicago Water Tower is completed.
The city's first vehicular tunnel is built below the Chicago River at Washington Street. Construction starts on a tunnel at LaSalle Street.
1871
The Great Chicago fire leaves 300 Chicagoans dead and 90,000 homeless. Property losses are estimated at $200 million.
1872
Aaron Montgomery Ward establishes the first mail-order business at Clark and Kinzie streets with the slogan "satisfaction guaranteed."
1873
Chicago Public Library is formed with the donation of 8,000 books from city residents. Queen Victoria and the people of Britain ship cartons of books to Chicago.
1885
The 9-story Home Insurance Building, the world's first "skyscraper," is erected on LaSalle Street.
1886
Eight Chicago policemen are killed during a workers' riot at Haymarket Square.
1889
Hull House is opened by Miss Jane Adams, helping hundreds of immigrants and others gain a place of self-respect in society.
1892
The first elevated trains begin operation.
1893
World's Columbian Exposition opens in commemoration of the 400th anniversary of the discovery of America by Columbus.
1895
The first automobile race in the United States is held along the Chicago lakefront with winning driver J. Frank Duryea averaging 7.5 miles per hour.
The Schwinn Bicycle Company is founded.
1900
Flow of the Chicago River is reversed to control pollution entering Lake Michigan.
The city's 500-mile streetcar system, along with the elevated railway system, provides 260 million annual rides, or about 160 rides for each Chicago resident.
1903
More than 600 people die in a fire at the Iroquois Theater.
1905
The first Rotary Club in America is founded in Chicago.
1907
University of Chicago physicist Abraham Michelson becomes the first American to win the Nobel Prize in physics.
1908
The City Clerk conducts the first registration of vehicles in the city, recording 36,778 one-horse vehicles, 16,900 multi-horse vehicles, and approximately 375 automobiles.
1910
Pioneer airman Walter Brookins flies over the lakefront before 20,000 adoring spectators.
The original Comiskey Park, home of the Chicago White Sox, opens at 35th Street and Shields Avenue.
1911
The present City Hall is dedicated.
1914
Wrigley Field, home of the Chicago Cubs, opens at Clark and Addison streets.
1915
Lake passenger steamer Eastland capsizes in the Chicago River, drowning 822 passengers.
1919
Real estate broker Archibald Teller opens the first Fannie May candy store.
Thirteen people die when the dirigible Winged Foot Express burns and crashes through the skylight of the Illinois Trust and Savings Bank.
1922
Louis Armstrong, a member of "King Oliver's Creole Jazz Band", becomes a mainstay in Chicago and helps to usher in the Jazz Age.
Flow of the Calumet River is reversed to help reduce pollution entering Lake Michigan.
1927
Chicago's first airport, the Chicago Municipal Airport, later known as Midway airport, is completed.
Kate Sturges Buckingham donates $750,000 to the city for construction of Buckingham Fountain as a memorial to her brother Clarence.
1929
John Graves Shedd presented the Shedd Aquarium as "a gift to the people of Chicago."
1930
Adler Planetarium opens through a gift from local merchant Max Adler.
The Merchandise Mart is built for $32 million by Marshall Field.
1931
Al Capone is found guilty of evading $231,000 in income taxes and sentenced by a Chicago federal court to 11 years in prison and fined $50,000.
1933
The Century of Progress world's fair opens on Northerly Island.
Chicago Mayor Anton Cermak is mortally wounded while riding in a car with President-elect Franklin Roosevelt.
The first All Star Game in baseball, played at Comiskey Park, attracts 47,595 fans. The first home run in All Star Game history is hit by Babe Ruth off pitcher Wild Bill Hallahan.
1934
John Dillinger is shot by the FBI near the alley next to the Biograph Theater, 2433 N. Lincoln Ave.
1936
The first Oscar Mayer "Wienermobile" rolls out of General Body Company's factory.
1937
A labor strike at Republic Steel results in the shooting deaths of 10 workers.
Chicago becomes the home of the first U.S. blood bank.
1942
Italian physicist Enrico Fermi achieves the first controlled release of nuclear energy on a squash court beneath the stands of Stagg Field at the University of Chicago.
The Chicago Cubs become the first team in baseball to install an organ to help motivate and entertain fans.
1943
State Street subway opens.
1949
The first daytime TV soap opera, "These Are My Children," is broadcast from Chicago's NBC studios.
1950
Chicago's population peaks at 3,620,962
1951
Dearborn Street subway opens.
1955
O'Hare International Airport opens.
1956
Eisenhower Expressway opens.
1958
Fire erupts at Our Lady of the Angels School, killing 90 students and three nuns.
The last streetcar runs in Chicago, signaling the end of what was once the largest streetcar system in the world.
1959
Comedy showcase "Second City" is founded on North Wells Street in a former Chinese laundry.
1960
Kennedy Expressway opens
1962
Dan Ryan Expressway opens
1964
Stevenson Expressway opens
1968
The James W. Jardine Water Purification Plant opens north of Navy Pier.
1969
The world's first commuter rail service on an expressway median opens on the Dan Ryan.
1971
The Chicago Union Stock Yards are closed.
1974
110-story Sears Tower is completed.
1979
Chicago's first woman mayor, Jane M. Byrne, takes office.
1981
"Spider" Dan Goodwin climbs both the Sears Tower and the John Hancock Center.
1983
Harold Washington is elected Chicago's first African-American mayor.
1991
Harold Washington Library Center opens as the new main branch of the Chicago Public Library.
Comiskey Park, the oldest ballpark in baseball, is demolished by White Sox owner Jerry Reinsdorf and his business associates. A new White Sox ballpark, built on the south side of 35th Street, opens.
1992
The "Great Chicago Flood" occurs when 124 million gallons of Chicago River water pours through a crack in the 47-mile network of freight tunnels under the central business district.
1994
Chicago hosts the opening ceremonies and first game of the first World Cup Soccer championship in the United States.
Historic Chicago Stadium is demolished by Bulls Chairman Jerry Reinsdorf and Blackhawks owner Bill Wirtz.
1995
An extended heat wave contributes to the deaths of more than 700 city residents.
1996
The Museum of Contemporary Art moves into the first new museum building constructed in Chicago in 60 years.
Chicago hosts the 1996 Democratic National Convention.
1997
The Chicago City Council approves a resolution absolving Mrs. O'Leary's cow of all blame for the Great Chicago Fire.
1998
Chicago Bulls win their sixth NBA Championship in 8 years.
2001
Chicago celebrates the Millennium.