Chicago holds 2,746,388 residents according to the 2020 United States Census, making it the third-largest city by population after New York City and Los Angeles. The title "Second City" emerged not from current population rankings but from Chicago's historical position as the nation's second-largest city through much of the twentieth century, a designation it held continuously from the 1890 census until Los Angeles overtook it in the 1990 count. The phrase has been reclaimed as civic identity rather than demographic fact, appearing in the name of the comedy theater founded in 1959 that launched careers including those of John Belushi, Bill Murray, Tina Fey, and Stephen Colbert.
The city occupies 234 square miles along the southwestern shore of Lake Michigan, with 28 miles of lakefront largely preserved as public space through Daniel Burnham's 1909 Plan of Chicago. The Chicago River flows backward, a reversal engineered in 1900 to prevent sewage from contaminating the drinking water supply drawn from the lake. The river divides the city into North Side, West Side, and South Side, with street numbering beginning at the intersection of State and Madison in the downtown Loop district named for the elevated train tracks that encircle the central business district in a rectangular pattern covering roughly one square mile.
The Great Chicago Fire of October 8-10, 1871 destroyed 3.3 square miles and left 100,000 residents homeless, creating conditions that allowed architects to reimagine urban construction on cleared land. The Home Insurance Building completed in 1885 at LaSalle and Adams Streets reached ten stories using a steel skeleton frame, a technique that defined the Chicago School of architecture and enabled vertical expansion previously impossible with load-bearing masonry. Louis Sullivan designed the Carson Pirie Scott Building completed in 1899 with its distinctive cast-iron ground floor ornamentation, establishing principles that influenced his protégé Frank Lloyd Wright, who maintained his studio in the suburb of Oak Park from 1889 to 1909.
Chicago deep-dish pizza appeared at Pizzeria Uno on Ohio Street in 1943, created by Ike Sewell and Ric Riccardo. The inverted structure places mozzarella cheese directly on the dough, followed by toppings, then crushed tomato sauce on top, baked in a round steel pan with sides typically measuring two to three inches high. A fourteen-inch pie requires 35 to 45 minutes in a deck oven. Lou Malnati's opened in 1971 in Lincolnwood, Gino's East opened in 1966 near Michigan Avenue, and Giordano's traces its stuffed pizza variant to 1974, each developing regional customer loyalty that persists across generations of Chicago families.
The elevated train system known as the "L" began operation in 1892 with the first section running along South Side Alley between Congress Street and 39th Street. The Chicago Transit Authority operates 224.1 miles of track across eight color-coded lines serving 146 stations, carrying an average of 423,000 weekday riders according to 2019 data, the second-highest rail ridership among United States cities after New York. The Brown Line runs above Wabash Avenue through the Loop, offering views into office windows at eye level, while the Red and Blue Lines operate 24 hours. A single ride costs 2.50 dollars when paid with a Ventra card, 3.00 dollars as cash fare on buses.
Navy Pier extends 3,300 feet into Lake Michigan from the mouth of the Chicago River, originally opened in 1916 as Municipal Pier to serve as a shipping and recreational facility. The Centennial Wheel installed in 2016 stands 196 feet tall with 42 enclosed gondolas, each holding up to eight passengers for rotations lasting approximately 13 minutes. The pier attracts an estimated nine million visitors annually, making it the most-visited attraction in the Midwest based on tourism bureau reporting, though actual verification of attendance counts proves difficult across multiple venues and free-access areas.
Millennium Park occupies 24.5 acres bounded by Michigan Avenue, Randolph Street, Columbus Drive, and Monroe Street, built atop rail yards and parking garages at a final cost exceeding 475 million dollars when it opened in 2004. Cloud Gate, the sculpture by Anish Kapoor locally called "The Bean," consists of 168 stainless steel plates welded together and polished to create a seamless reflective surface measuring 66 feet long, 33 feet high, and weighing 110 tons. The Crown Fountain features two 50-foot glass block towers designed by Jaume Plensa that project video images of Chicago residents' faces, with water flowing from a spout positioned at mouth level, operating from May through October.
The Art Institute of Chicago maintains a collection of approximately 300,000 works, with particular depth in Impressionist and Post-Impressionist painting including Georges Seurat's "A Sunday on La Grande Jatte" measuring 81.7 by 121.25 inches, completed in 1886 using a pointillist technique involving thousands of individual color dots. Grant Wood's "American Gothic" from 1930 depicts a farmer and woman in front of a Carpenter Gothic house in Eldon, Iowa, though it resides permanently in the museum's American galleries. The bronze lions flanking the Michigan Avenue entrance were installed in 1894, cast by Edward Kemeys, each weighing two tons and standing in poses identified as "on the prowl" to the south and "in an attitude of defiance" to the north.
The University of Chicago enrolled its first students in 1892 funded by oil magnate John D. Rockefeller's initial gift of 600,000 dollars, eventually totaling 35 million dollars across subsequent donations. The university has produced 94 Nobel Prize laureates among faculty, students, and researchers, the fourth-highest count globally among institutions. Enrico Fermi led the team that achieved the first controlled nuclear chain reaction on December 2, 1942 beneath Stagg Field, an event commemorated by Henry Moore's "Nuclear Energy" sculpture installed in 1967 on the site at Ellis Avenue and 56th Street.
Wrigley Field opened on April 23, 1914 at the intersection of Clark and Addison Streets as Weeghman Park, renamed in 1927 after chewing gum manufacturer William Wrigley Jr. acquired the team. The outfield ivy was planted in 1937 by Bill Veeck, combining Boston ivy and Japanese bittersweet that turns brick-red each October. The manually operated scoreboard installed in 1937 weighs 57,100 pounds, stands 27 feet above the center field bleachers, and displays scores from other games using numerals changed by hand by workers inside the structure. The Cubs ended a 108-year championship drought on November 2, 2016 by winning the World Series against Cleveland in ten innings of Game Seven, triggering an estimated five million attendance at the victory parade along Michigan Avenue four days later.
Chicago's lakefront bicycle path extends 18.5 miles from Edgewater to South Shore, designated as part of the larger Lakefront Trail that continues north into Evanston and south toward Indiana. The 606 elevated trail converted 2.7 miles of former Bloomingdale railway line into a pedestrian and cycling path that opened in 2015, running from Ashland Avenue to Walsh Park with six access points and vegetation including 270 trees and 62,000 plantings. The trail rises 17 feet above street level, providing clear sightlines across residential neighborhoods on the North Side.
The Chicago Riverwalk reconstruction completed between 2009 and 2016 created a continuous 1.25-mile pedestrian path from Lake Michigan to Lake Street with six distinct sections named The Marina, The Cove, The River Theater, The Water Plaza, The Jetty, and The Boardwalk. The dyeing of the Chicago River green for Saint Patrick's Day began in 1962 using 100 pounds of vegetable-based dye that turns the water emerald for approximately five hours, with the formula and exact composition held privately by the plumbers union members who perform the dyeing from motorboats each March 17th.